Broken Plex Scanner Files must be copied to computer and back the server to work [Solved]

Hi,
I’m trying to have Plex recognise a Serie with several Seasons. At the begining all the seasons were all in the same folder and the filename was not following the Plex folder structure. Just to try I created a folder named “Season 01” and COPIED 3 chapters and renames them as in the Plex instructions “SERIE NAME - s01e01.mkv”. After several rescans it finally recognized these 3 files. I renames them back to how they were before (SERIE NAME 01x01.mkv) and they were still recognized by Plex in the next scan. So I moved all chapters to its season folder and added to the name the - slash to comply with the Plex instructions. But none of the chapters nor any other season gets recognized other than the 3 previously working chapters… why is this happening? Is Plex caching previously scanned files (even when renamed?) Or what’s going on? The season folders do appear in the event log… but no chapter is registered… any idea how to fix this? (I have other series also on the same server, but they all get found properly).

EDIT:

It seems that I found out how to make Plex see the files. It works when I copy the files from the server to the computer, and back to the server. Copying the files with the CP command on the server doesn’t have the same effect. What is going on? How to make this work properly?

CONCLUSION:
It was a permission issue.

it’s TV Shows > SERIES NAME > Season XX > SERIES NAME - sXXeYY.mkv with XX being the 2-digit season and YY the episode number… not SERIE NAME XXxYY.mkv!
Plex will ignore all files that don’t have a sXXeYY pattern when scanning for a tv show media kind section.

https://support.plex.tv/articles/201543057-why-is-some-of-my-content-not-found/

So at the end, and after copying back and forth 60 GB of serie data over samba, I finally found out the problem. It was not an issue with Plex, but with permissions. I have the Series in my personal folder for my personal account, Plex can access that folder with the “Other” permission, which was set to 0 without me noticing. So setting the correct Read permissions for Others fixed the issue.

One curiosity that came out of this is that the serie still uses the “SERIE NAME XXxYY.mkv” format and not the “SERIES NAME - sXXeYY.mkv” format as written in the https://support.plex.tv/articles/201543057-why-is-some-of-my-content-not-found/ article. It seems to work in both ways. Nice!