Hm, this looks all normal.
I just noticed that you are on a server version which has a bug related to the automatic track selection. Update your server version to at least 1.18.5
Then:
- restore the language settings on your account to “Selected German, German, on foreign language and prefer forced subtitles.”
- then perform the Plex Dance with the movie
Make sure none of your clients is still on the movie’s preplay page. Set them all back to the home page.
Let it sit for a few minutes afterwards, then enter this movie’s preplay page again.