Should I expect playback to resume on a mp4 streamed from Plex ?
I start playback, hit done or leave the app for a while. Go back in and it starts from the beginning.
I have ‘Resume Playback’ set as ON.
Thanks
What button or control are you using for “Done”.
How are you “leaving” the app? Quitting, force quitting, long pressing the home button, etc?
A mp4 should resume just like the other video containers.
Do MKVs resume when you do the same as mp4s?
Sorry probably should have given more info 
Using iPadOS - the Done button is top left.
I just leave the app by Command H on a Magic Keyboard, don’t force quit.
Will find a MKV and try it.
Doesn’t really have to be just a MKV, just do any other containers work differently than the mp4 for resume? avi, mov, etc.