Actions leaking to following test when testing effects

[DaSchTour]

I have a simple effect

delete = createEffect(
    () => {
      return this.actions$.pipe(
        ofType(Actions.delete),
        tap((action) => this.blobStore.delete(action.id)),
      );
    },
    { dispatch: false },
  );

Then I've written some tests like this (I'm using spectator but I guess/hope that's not the issue)

it('should call delete on blobStore with id', () => {
    const blobStore = spectator.inject(BLOB_STORE);

    actions$ = of(Actions.delete({ id: 'first id' }));

    const sub = spectator.service.delete.subscribe();
    expect(blobStore.delete).toHaveBeenCalledWith('first id');
  });

  it('should call delete on blobStore for every action', () => {
    const blobStore = spectator.inject(BLOB_STORE);

    actions$ = of(
      Actions.delete({ id: 'second id' }),
      Actions.delete({ id: 'third id' }),
    );

    spectator.service.delete.subscribe();
    expect(blobStore.delete).toHaveBeenCalledWith('second id', 'third id');
  });

The setup with actions$ is done as described in the documentation.
The issue is, that the toHaveBeenCalledWith shows me that it is called 3 times and the first time is with the id from the test before.

I have configured my service to be destroyed after each test. But somehow that doesn't help. I'm quite confused how this is possible.