Why are pipe() and subscribe() not firing after post() Angular 12

Question

I am not getting any kind of follow-up on a post call in this function

upload(media: Media, data: Array<number>) {
    let path: string = '';
    if (media != null && media.id == null) {
      path = `${this.restPrefix}/${this.appConfig.modIds.media}/upload`;
    } else {
      path = `${this.restPrefix}/${this.appConfig.modIds.media}/uploadAndReplace`;
    }
    const formData = new FormData();

    const fileData = new Blob([new Uint8Array(data)]);
    formData.append(
      "file",
      fileData,
      'blank',
    );

    if (media.id != null) {
      formData.append('id',media.id);
    }
    if (media.title != null) {
      formData.append('title',media.title);
    }
    if (media.caption != null) {
      formData.append('caption',media.caption);
    }

    return this.http.post<any>(
      path,
      formData,
      { headers: this.headersSrv.getMediaHeaders() })
      .pipe(
        tap((r) => {
          if (this.debug) { console.log(`upload response ${r}`); }
        }),
        catchError(e => { return throwError(e); })
      );
  }

When I invoke the function

this.mediaSrv.upload(metadata, file).subscribe(
              (r) => { console.log(r); input.responseText = r; },
              (e) => {}
            );

I don't see either the console.log message in the tap() or the follow-up .subscribe() as if neither are firing.

However, I can see in the Network tab that I do get a good response back. So, why isn't .subscribe() or .tap() working? Every other post call I have is running and logging debug messages.