Server Version#: 1.31.1.6733
Player Version#: 9.16.2.38798 (Android Pixel 7)
If you hold select an item anywhere in the app and select mark as watched, the UI then presents the mark as unwatched confirmation prompt. It is also same for mark as unwatched presenting the mark as watched UI confirmation prompt.
Despite the incorrect confirmation prompt appearing the action of what you select is correct.
So for example if I select a movie and then select mark as unwatched, it will ask if I want to mark as watched. If I then select yes the movie is marked as unwatched despite the incorrect confirmation prompt.