diff --git a/src/tools/esbuild/angular-bundler.spec.ts b/src/tools/esbuild/angular-bundler.spec.ts
index 11b94dc..a93b16f 100644
--- a/src/tools/esbuild/angular-bundler.spec.ts
+++ b/src/tools/esbuild/angular-bundler.spec.ts
@@ -166,4 +166,24 @@ describe('createAngularEsbuildContext', () => {
       ngJitMode: 'false',
     });
   });
+
+  // #145: the #128 fix only covered the app build; exposes still inlined synthesized deep imports.
+  it('externalizes synthesized deep imports into shared mappings', async () => {
+    await createAngularEsbuildContext(
+      makeOptions({ mappedPaths: { [path.join(workspaceRoot, 'libs/ui/src/index.ts')]: '@myorg/ui' } }),
+      'mapping-or-exposed'
+    );
+
+    expect(lastBuildOptions().plugins!.map(p => p.name)).toEqual([
+      'angular-compiler',
+      'nf-shared-mappings',
+      'commonjs',
+    ]);
+  });
+
+  it('leaves the plugin out without shared mappings', async () => {
+    await createAngularEsbuildContext(makeOptions(), 'mapping-or-exposed');
+
+    expect(lastBuildOptions().plugins!.map(p => p.name)).toEqual(['angular-compiler', 'commonjs']);
+  });
 });
diff --git a/src/tools/esbuild/angular-bundler.ts b/src/tools/esbuild/angular-bundler.ts
index 656aa8e..37b2e51 100644
--- a/src/tools/esbuild/angular-bundler.ts
+++ b/src/tools/esbuild/angular-bundler.ts
@@ -17,6 +17,7 @@ import { normalizeOptimization, normalizeSourceMaps } from '../../utils/normaliz
 import { createAwaitableCompilerPlugin } from './create-awaitable-compiler-plugin.js';
 import type { NormalizedContextOptions } from '../../utils/normalize-context-options.js';
 import { writeContextTsConfig } from './write-context-tsconfig.js';
+import { createSharedMappingsPlugin } from './shared-mappings-plugin.js';
 
 export async function createAngularEsbuildContext(
   options: NormalizedContextOptions,
@@ -36,6 +37,7 @@ export async function createAngularEsbuildContext(
     hash,
     chunks,
     platform,
+    mappedPaths,
   } = options;
 
   const federationTsConfig = options.tsConfigPath;
@@ -172,7 +174,13 @@ export async function createAngularEsbuildContext(
     format: 'esm',
     target: target,
     logLimit: 0,
-    plugins: [compilerPlugin, commonjsPlugin(), ...customPlugins],
+    plugins: [
+      compilerPlugin,
+      // Angular's synthesized deep imports would otherwise inline a second copy of a mapped lib.
+      ...(Object.keys(mappedPaths).length > 0 ? [createSharedMappingsPlugin(mappedPaths)] : []),
+      commonjsPlugin(),
+      ...customPlugins,
+    ],
     define: {
       ...builderOptions.define,
       ...(dev ? {} : { ngDevMode: 'false' }),