Scanning library overwrites custom metadata of existing films - please help

[JuiceWSA]

Embedded Titles in your MP4 files?

Do this:

Video File Naming

With LMA in priority, Embedded Titles within MP4/M4V files are preferred - even over a perfect file name. Local Media Assets should - AT ALL TIMES - remain enabled (unless specifically instructed to turn it off). Local Media Assets should be ‘Demoted’, to the bottom of the stack of active agents under ALL tabs in Shows and Movies, but should NOT be disabled. Local Media Assets is needed for many things - it doesn’t need to be given Tip-Top-Priority (as Plex has so hatefully placed it as it’s …

You should now be able to edit safely.