multiple using of tap() causes a false error

Describe the bug

the following code is correct, but will generate a false error

import { Observable, of, tap } from 'rxjs';

let test$: Observable<number> = of(1).pipe(
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
  tap(() => 1),
);

Error:

Type 'Observable<unknown>' is not assignable to type 'Observable<number>'.
  Type 'unknown' is not assignable to type 'number'.ts(2322)

commenting any of tap() blocks causes the error to be disappeared.

also, explicitly set the type again resolves the error. but TS can infer the type easily

of(1).pipe( ... ) as Observable<number>

Expected behavior

no error

Reproduction code

No response

Reproduction URL

https://stackblitz.com/edit/rxjs-jvajmd?devtoolsheight=60&file=index.ts,tsconfig.json

Version

next

Environment

No response

Additional context

No response

Start with the linked StackBlitz reproduction, especially index.ts and tsconfig.json, and reduce the example to repeated tap() calls while checking the inferred type. Done means the shown Observable assignment compiles without an explicit type assertion and the false error no longer appears.