Numerous features missing or not working after moving library

I recently moved all of my library files to an external drive (rather than hosting within my PC) and it seems that during this move, I did something that has removed some features I used to rely on (or they disappeared some other way). Such as:

Chapter select for the movies I have in my collection (I don’t see the option for any movies like I used to)

Autoplay in playlists when starting in the middle (I have to start from the first movie, then skip to whatever movie I want to watch, and then it will auto-play through the rest. It definitely did not do this before).

Anyway…Any suggestions or ideas?

Which Plex player are you using?

If they were server created chapters and it thought they were new files then the it might have to recreate the chapters. How did you move the files?

I copied the entire library to the new drive, had Plex create a new library location on the new drive, erased the old one, and scanned the new drive for new files. The library auto-populated.