I have several files that MC won't rename or move, while a file manager or from terminal there is no issue.
I tried a few things, and found that for the first 3 files, a particular character was causing it.
This filename did not rename or move:
/mnt/Data/Music Leftover/Joe Satriani/[1995] Joe Satriani/11 - (You`re) My World.flac
After manually renaming and reimporting, it would:
/mnt/Data/Zooi/Music Leftover/Joe Satriani/[1995] Joe Satriani/11 - (You're) My World.flac
The same goes for 2 other files with the same character.
Other files had a $-sign. For instance:
/mnt/Data/Music Leftover/Metallica/[1987] The $5.98 E.P. Garage Days Re-Revisited/02 - So What_.flac
The file would not move because the album title has a $ and the move rule was like [Artist]/[Album]/...
When I removed the $-sign from the tag the file moved perfectly.
Editing the tag alone was not enough; MC will not rename a file if the filename has an "invalid" character, or move if the file or directory has an "invalid" character. Manually removing these characters, reimporting them and then rename/move was the only option.