diff --git a/apps/rxjs-pipe-bug/.eslintrc.json b/apps/rxjs-pipe-bug/.eslintrc.json
new file mode 100644
index 0000000..028ce09
--- /dev/null
+++ b/apps/rxjs-pipe-bug/.eslintrc.json
@@ -0,0 +1,36 @@
+{
+  "extends": ["../../.eslintrc.json"],
+  "ignorePatterns": ["!**/*"],
+  "overrides": [
+    {
+      "files": ["*.ts"],
+      "extends": [
+        "plugin:@nrwl/nx/angular",
+        "plugin:@angular-eslint/template/process-inline-templates"
+      ],
+      "rules": {
+        "@angular-eslint/directive-selector": [
+          "error",
+          {
+            "type": "attribute",
+            "prefix": "app",
+            "style": "camelCase"
+          }
+        ],
+        "@angular-eslint/component-selector": [
+          "error",
+          {
+            "type": "element",
+            "prefix": "app",
+            "style": "kebab-case"
+          }
+        ]
+      }
+    },
+    {
+      "files": ["*.html"],
+      "extends": ["plugin:@nrwl/nx/angular-template"],
+      "rules": {}
+    }
+  ]
+}
diff --git a/apps/rxjs-pipe-bug/README.md b/apps/rxjs-pipe-bug/README.md
new file mode 100644
index 0000000..4b02cdf
--- /dev/null
+++ b/apps/rxjs-pipe-bug/README.md
@@ -0,0 +1,35 @@
+<h1>Rxjs pipe bug</h1>
+
+> Author: Thomas Laforge
+
+<!-- TODO: add Information/Statement/Rules/Constraint/Steps -->
+
+### Information
+
+### Statement
+
+### Step 1
+
+### Step 2
+
+### Constraints:
+
+### Submitting your work
+
+1. Fork the project
+2. clone it
+3. npm install
+4. **nx serve rxjs-pipe-bug**
+5. _...work on it_
+6. Commit your work
+7. Submit a PR with a title beginning with **Answer:11** that I will review and other dev can review.
+
+<!-- TODO: add challenge number and project Name -->
+
+<a href="https://github.com/tomalaforge/angular-challenges/pulls?q=label%3A11+label%3Aanswer"><img src="https://img.shields.io/badge/-Solutions-green" alt="Rxjs pipe bug"/></a>
+
+<!-- TODO: uncomment when done late -->
+<!-- <a href='https://github.com/tomalaforge/angular-challenges/pulls?q=label%3A11+label%3A"answer+author"'><img src="https://img.shields.io/badge/-Author solution-important" alt="{Project name} solution author"/></a>
+<a href="{Blog post url}" target="_blank" rel="noopener noreferrer"><img src="https://img.shields.io/badge/-Blog post explanation-blue" alt="{Project name} blog article"/></a> -->
+
+_You can ask any question on_ <a href="https://twitter.com/laforge_toma" target="_blank" rel="noopener noreferrer"><img src="./../../logo/twitter.svg" height=20px alt="twitter"/></a>
diff --git a/apps/rxjs-pipe-bug/project.json b/apps/rxjs-pipe-bug/project.json
new file mode 100644
index 0000000..90b7abe
--- /dev/null
+++ b/apps/rxjs-pipe-bug/project.json
@@ -0,0 +1,81 @@
+{
+  "name": "rxjs-pipe-bug",
+  "$schema": "../../node_modules/nx/schemas/project-schema.json",
+  "projectType": "application",
+  "sourceRoot": "apps/rxjs-pipe-bug/src",
+  "prefix": "app",
+  "targets": {
+    "build": {
+      "executor": "@angular-devkit/build-angular:browser",
+      "outputs": ["{options.outputPath}"],
+      "options": {
+        "outputPath": "dist/apps/rxjs-pipe-bug",
+        "index": "apps/rxjs-pipe-bug/src/index.html",
+        "main": "apps/rxjs-pipe-bug/src/main.ts",
+        "polyfills": ["zone.js"],
+        "tsConfig": "apps/rxjs-pipe-bug/tsconfig.app.json",
+        "inlineStyleLanguage": "scss",
+        "assets": [
+          "apps/rxjs-pipe-bug/src/favicon.ico",
+          "apps/rxjs-pipe-bug/src/assets"
+        ],
+        "styles": ["apps/rxjs-pipe-bug/src/styles.scss"],
+        "scripts": []
+      },
+      "configurations": {
+        "production": {
+          "budgets": [
+            {
+              "type": "initial",
+              "maximumWarning": "500kb",
+              "maximumError": "1mb"
+            },
+            {
+              "type": "anyComponentStyle",
+              "maximumWarning": "2kb",
+              "maximumError": "4kb"
+            }
+          ],
+          "outputHashing": "all"
+        },
+        "development": {
+          "buildOptimizer": false,
+          "optimization": false,
+          "vendorChunk": true,
+          "extractLicenses": false,
+          "sourceMap": true,
+          "namedChunks": true
+        }
+      },
+      "defaultConfiguration": "production"
+    },
+    "serve": {
+      "executor": "@angular-devkit/build-angular:dev-server",
+      "configurations": {
+        "production": {
+          "browserTarget": "rxjs-pipe-bug:build:production"
+        },
+        "development": {
+          "browserTarget": "rxjs-pipe-bug:build:development"
+        }
+      },
+      "defaultConfiguration": "development"
+    },
+    "extract-i18n": {
+      "executor": "@angular-devkit/build-angular:extract-i18n",
+      "options": {
+        "browserTarget": "rxjs-pipe-bug:build"
+      }
+    },
+    "lint": {
+      "executor": "@nrwl/linter:eslint",
+      "options": {
+        "lintFilePatterns": [
+          "apps/rxjs-pipe-bug/**/*.ts",
+          "apps/rxjs-pipe-bug/**/*.html"
+        ]
+      }
+    }
+  },
+  "tags": []
+}
diff --git a/apps/rxjs-pipe-bug/src/app/app.component.ts b/apps/rxjs-pipe-bug/src/app/app.component.ts
new file mode 100644
index 0000000..b0c6951
--- /dev/null
+++ b/apps/rxjs-pipe-bug/src/app/app.component.ts
@@ -0,0 +1,56 @@
+/* eslint-disable @angular-eslint/component-selector */
+import { AsyncPipe, NgFor } from '@angular/common';
+import { Component, inject, Input } from '@angular/core';
+import { BehaviorSubject, take } from 'rxjs';
+import { AppService } from './app.service';
+import { TopicType } from './localDB.service';
+
+@Component({
+  standalone: true,
+  selector: 'button-delete-topic',
+  imports: [AsyncPipe],
+  template: `
+    <button (click)="deleteTopic()"><ng-content></ng-content></button>
+    <div>{{ message$$ | async }}</div>
+  `,
+})
+export class ButtonDeleteComponent {
+  @Input() topic!: TopicType;
+
+  message$$ = new BehaviorSubject<string>('');
+
+  private service = inject(AppService);
+
+  deleteTopic() {
+    this.service
+      .deleteOldTopics(this.topic)
+      .pipe(take(1))
+      .subscribe((result) =>
+        this.message$$.next(
+          result
+            ? `All ${this.topic} have been deleted`
+            : `Error: deletion of some ${this.topic} failed`
+        )
+      );
+  }
+}
+
+@Component({
+  standalone: true,
+  imports: [AsyncPipe, NgFor, ButtonDeleteComponent],
+  selector: 'app-root',
+  template: `
+    <div *ngFor="let item of all$ | async">
+      {{ item.id }} - {{ item.topic }}
+    </div>
+
+    <button-delete-topic topic="food">Delete Food</button-delete-topic>
+    <button-delete-topic topic="sport">Delete Sport</button-delete-topic>
+    <button-delete-topic topic="book">Delete Book</button-delete-topic>
+  `,
+})
+export class AppComponent {
+  private service = inject(AppService);
+
+  all$ = this.service.getAll$;
+}
diff --git a/apps/rxjs-pipe-bug/src/app/app.service.ts b/apps/rxjs-pipe-bug/src/app/app.service.ts
new file mode 100644
index 0000000..09a9ed1
--- /dev/null
+++ b/apps/rxjs-pipe-bug/src/app/app.service.ts
@@ -0,0 +1,23 @@
+import { inject, Injectable } from '@angular/core';
+import { merge, mergeMap, Observable, of, take } from 'rxjs';
+import { LocalDBService, TopicType } from './localDB.service';
+
+@Injectable({ providedIn: 'root' })
+export class AppService {
+  private dbService = inject(LocalDBService);
+
+  getAll$ = this.dbService.infos$;
+
+  deleteOldTopics(type: TopicType): Observable<boolean> {
+    return this.dbService.searchByType(type).pipe(
+      take(1),
+      mergeMap((topicToDelete) =>
+        topicToDelete.length > 0
+          ? topicToDelete
+              .map((t) => this.dbService.deleteOneTopic(t.id))
+              .reduce((acc, curr) => merge(acc, curr), of(true))
+          : of(true)
+      )
+    );
+  }
+}
diff --git a/apps/rxjs-pipe-bug/src/app/localDB.service.ts b/apps/rxjs-pipe-bug/src/app/localDB.service.ts
new file mode 100644
index 0000000..710c62f
--- /dev/null
+++ b/apps/rxjs-pipe-bug/src/app/localDB.service.ts
@@ -0,0 +1,58 @@
+/* eslint-disable @typescript-eslint/member-ordering */
+import { Injectable } from '@angular/core';
+import { randNumber } from '@ngneat/falso';
+import { ComponentStore } from '@ngrx/component-store';
+import { of } from 'rxjs';
+
+export type TopicType = 'food' | 'book' | 'sport';
+
+interface Info {
+  id: number;
+  topic: TopicType;
+}
+
+interface DBState {
+  infos: Info[];
+}
+
+const initialState: DBState = {
+  infos: [
+    { id: 1, topic: 'book' },
+    { id: 2, topic: 'book' },
+    { id: 3, topic: 'book' },
+    { id: 4, topic: 'book' },
+    { id: 5, topic: 'food' },
+    { id: 6, topic: 'food' },
+    { id: 7, topic: 'book' },
+    { id: 8, topic: 'book' },
+    { id: 9, topic: 'book' },
+    { id: 10, topic: 'sport' },
+  ],
+};
+
+@Injectable({ providedIn: 'root' })
+export class LocalDBService extends ComponentStore<DBState> {
+  constructor() {
+    super(initialState);
+  }
+
+  infos$ = this.select((state) => state.infos);
+
+  searchByType = (type: TopicType) =>
+    this.select((state) => state.infos.filter((i) => i.topic === type));
+
+  deleteOne = this.updater(
+    (state, id: number): DBState => ({
+      infos: state.infos.filter((i) => i.id !== id),
+    })
+  );
+
+  deleteOneTopic = (id: number) => {
+    const randomNumber = randNumber({ min: 0.1, max: 1, fraction: 2 });
+    if (randomNumber > 0.5) {
+      this.deleteOne(id);
+      return of(true);
+    }
+    return of(false);
+  };
+}
diff --git a/apps/rxjs-pipe-bug/src/assets/.gitkeep b/apps/rxjs-pipe-bug/src/assets/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/apps/rxjs-pipe-bug/src/favicon.ico b/apps/rxjs-pipe-bug/src/favicon.ico
new file mode 100644
index 0000000..317ebcb
Binary files /dev/null and b/apps/rxjs-pipe-bug/src/favicon.ico differ
diff --git a/apps/rxjs-pipe-bug/src/index.html b/apps/rxjs-pipe-bug/src/index.html
new file mode 100644
index 0000000..caa71f3
--- /dev/null
+++ b/apps/rxjs-pipe-bug/src/index.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <title>RxjsPipeBug</title>
+    <base href="/" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <link rel="icon" type="image/x-icon" href="favicon.ico" />
+  </head>
+  <body>
+    <app-root></app-root>
+  </body>
+</html>
diff --git a/apps/rxjs-pipe-bug/src/main.ts b/apps/rxjs-pipe-bug/src/main.ts
new file mode 100644
index 0000000..31c5da4
--- /dev/null
+++ b/apps/rxjs-pipe-bug/src/main.ts
@@ -0,0 +1,4 @@
+import { bootstrapApplication } from '@angular/platform-browser';
+import { AppComponent } from './app/app.component';
+
+bootstrapApplication(AppComponent).catch((err) => console.error(err));
diff --git a/apps/rxjs-pipe-bug/src/styles.scss b/apps/rxjs-pipe-bug/src/styles.scss
new file mode 100644
index 0000000..90d4ee0
--- /dev/null
+++ b/apps/rxjs-pipe-bug/src/styles.scss
@@ -0,0 +1 @@
+/* You can add global styles to this file, and also import other style files */
diff --git a/apps/rxjs-pipe-bug/tsconfig.app.json b/apps/rxjs-pipe-bug/tsconfig.app.json
new file mode 100644
index 0000000..e0e9bfb
--- /dev/null
+++ b/apps/rxjs-pipe-bug/tsconfig.app.json
@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "types": []
+  },
+  "files": ["src/main.ts"],
+  "include": ["src/**/*.d.ts"],
+  "exclude": ["jest.config.ts", "**/*.test.ts", "**/*.spec.ts"]
+}
diff --git a/apps/rxjs-pipe-bug/tsconfig.editor.json b/apps/rxjs-pipe-bug/tsconfig.editor.json
new file mode 100644
index 0000000..0f9036b
--- /dev/null
+++ b/apps/rxjs-pipe-bug/tsconfig.editor.json
@@ -0,0 +1,7 @@
+{
+  "extends": "./tsconfig.json",
+  "include": ["**/*.ts"],
+  "compilerOptions": {
+    "types": []
+  }
+}
diff --git a/apps/rxjs-pipe-bug/tsconfig.json b/apps/rxjs-pipe-bug/tsconfig.json
new file mode 100644
index 0000000..0b22c5f
--- /dev/null
+++ b/apps/rxjs-pipe-bug/tsconfig.json
@@ -0,0 +1,29 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "files": [],
+  "include": [],
+  "references": [
+    {
+      "path": "./tsconfig.app.json"
+    },
+    {
+      "path": "./tsconfig.editor.json"
+    }
+  ],
+  "compilerOptions": {
+    "target": "es2022",
+    "useDefineForClassFields": false,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "angularCompilerOptions": {
+    "enableI18nLegacyMessageIdFormat": false,
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  }
+}