It looks like I'm having this issue too. I have one flac file showing as unknown artist/album that I tagged using foobar2000 and checked using TagScanner and both appear to have no issue. Windows seems to recognize it fine as well.
I tried what was suggested in this thread by removing the file, full rescan, add file, full rescan but looks like it still won't work. I've tried reapplying the tags using TagScanner but doesn't look like anything has changed.
I'm on version v3-build-874-arm64-play
link to file
