Is there a .cue file in the same directory? I had the same problem. Turns out the .cue file defined the track names (albeit wrongly) but there was no band nor album definition in the .cue file. I removed the .cue and deleted the album from my phone, then copied the album over again without the .cue file. Full rescan and bingo, job done.
Just in case it's useful, I replied with the same method to this problem as well:
"Unknown artist"/"Unknown album" even though files have tags. Missing tags also keep changing
in Poweramp Bug Reports
Posted
Is there a .cue file in the same directory? I had the same problem. Turns out the .cue file defined the track names (albeit wrongly) but there was no band nor album definition in the .cue file. I removed the .cue and deleted the album from my phone, then copied the album over again without the .cue file. Full rescan and bingo, job done.
Just in case it's useful, I replied with the same method to this problem as well: