Hi
This is also happening to me, I am running on Linux with plex last beta version, I also mentioned a few weeks ago on twitter about this issue.
it’s impossible to you to check all the logs about this issue, it occurs on many systems, win linux, impossible that you cannot see it your self in a lab or something
It only happen in big libraries
All cores go to 100%
Logs stop in normal scan process
Also try to use plexignore for extrathumb extra art jpg png etc
Database maintenance and export restore
In the logs I can only see, a new diferent message
WARN - Held transaction for too long
For what I saw here in forum and related to this message is that version 1.17.0.1841
Thx and Merry Xtmas