In the mobile app I sometimes use the function open covers.
If you have open a cover full screen you can then browse through all your movies by swiping left and right. If you then click on the image again, the full screen images is closed and you and up at the movie of the cover you just closed. Works fine. However:
If you go to a movie that has a back cover. Open the back cover in full screen. Then swiping does nothing. Okay fine. But if you now click on the image again to close it, you don’t return to the movie you just opened the back cover from. But you end up at the first movie from the movies list (in whatever order you have them sorted).
Expected behavior: at least go back to the movie you came from when you close the back cover (after incidentally swiping).
You can also think about stuff like: when I have the cover opened, why can you not go the the back cover from that? Then swiping could always go to the next movie either you opened the back or front cover.
Android btw.