Hard to believe I would have missed it at the top of the list.
Anyway… discussed this in another thread a few days ago (linked below).
Net result for Android mobile is:
- If you log in with a Plex Pass account, subtitle offset appears.
- If you log in with a non-Plex Pass account, subtitle offset does not appear.
- Documentation does not say a Plex Pass account is required.
- Unclear if working as designed or if this is a bug. Plex will have to get involved.