The problem is the media scanner is generating a checksum property for the file which it HOLDS ON TO FOREVER AND EVER.
It’s mentioned upthread that if a file changes this will trigger a rescan of the file. This is fine and good, except the checksum property IS NEVER CHANGED.
If you had two files added at different times, and each file was momentarily empty when added, and plex scanned each file, plex now marks each file separately with the empty file checksum. Later on, plex looks at this checksum property THAT NEVER CHANGES and thinks … oh these have matching checksum properties! Clearly they are versions of the same content!
This part is a bit speculative but I wouldn’t be surprised if you add a file with the wrong name and it is a complete file, then Plex may match it incorrectly. You rename the file, rematch it, things look good. What happens if you then add a new file which really is the thing it incorrectly matched to previously? Is it going to see a relationship with that checksum and the old hash? I really don’t know but it wouldn’t surprise me at this point.
