Files using APEv2 tags are not properly scanned by Plex Media Scanner. Music files with APEv2 and also ID3v1 tags are also not scanned, the ID3v1 tags are completely ignored and the file is left as Unknown!
This bug has existed for more than 4 years and should be fixed. Every other music player I have tried (Kodi, FooBar2000, Squeezebox, MPD, Emby and even WinAMP) can read these APEv2 tags.
Mutagen, the underlying Python tag library which Plex uses, supports APEv2 tags so please can the Plex team make use of these tags? http://mutagen.readthedocs.io/en/latest/api/ape.html