Missing metadata for mp3 - private music

Server Version#: 4.49.2 (QNAP)
Player Version#: n/a

Today I’ve encountered a problem I’ve not seen before, where I’m adding an MP3 into my collection.
The file is from a friend, not a commerical CD, so there won’t be any public metadata for it.

The MP3 has the following fields set correctly according to both MediaMonkey and MP3Tag.

Album Name = (Blank as there isn’t one)
Track Name - is set
Album Artist - is set
Artist - is set

But PLEX isn’t reading in Track Name or Artist

According to the logs:

*I’ve **** the name out for privacy:

com.plexapp.agents.localmedia.log

2021-01-01 16:42:51,839 (7fcdbe834700) : INFO (audiohelpers:171) - Reading ID3 tags from: /share/CE_CACHEDEV1_DATA/Music/Various Artists/Unknown/12 # Dec 2020 track # Lauren *****.mp3
2021-01-01 16:42:51,843 (7fcdbe834700) : INFO (audiohelpers:174) - Found tags: [‘TDRC’, u’TXXX:replaygain_track_peak’, u’TXXX:replaygain_track_gain’, ‘TRCK’, ‘TPE2’, ‘TPE1’, ‘TIT2’, u’TXXX:replaygain_album_gain’, ‘TSSE’]

But from that log it’s not really giving detail of why its not reading the other metadata in.

I’ve re-edited the file, moved it to force a rescan etc…
It’d be nice if PLEX had a feature to force a full rescan, that then gave a verbose report of what it found (at the field level).

Note: i just realised the log entry there is from when I Moved the file out to another location to try and trigger a new scan of the file… I moved it back again but thats not showing in the log for some reason.

I put the missing fields in Red in the pic.
The Track Title should be “Dec 2020 track” and the Artist name should be the same as the Album Artist.

I also looked at the Prefer Local metadata is checked too.

… and I know I can manually edit the data in PLEX… I’m just trying to find out why the existing metadata isn’t being read in from the MP3.