Some very useful info’ there - thanks.
I’ve been exchanging emails with the author of Mp3Tags and he made the same suggestion (REMOVE tags then UNDO). Unfortunately, the UNDO appears to also restore whatever is causing the problem.
At this point, I think I’ve spent more time trying to fix this than it would have taken me to manually tag album by album (for artist, album name) and track by track for title for the handful of albums I’ve converted to date. I’d still really like to know what’s at issue, though, as I have dozens more albums I want to rip.
I downloaded and installed MP3 Diags. That is one COMPLICATED UI. I’m not sure it’s worth the time to get good at it when I might be able to fix the files manually in less time than it would take to become proficient with the tool.
Open Mp3tag “Options” (CTRL+O), find this tab, and make selects match the image:
If still issues, consider writing only ID3v1 tags.
That makes sense… But it’s OK if you remove and then manually tag?
Way back in your 1st post you said you’d tried removing the tag…
If they’re from vinyl I assume you’ve been manually tagging them anyway…
And it doesn’t take THAT long. You can select a folder-full of files (an album) and type-in all of the common information once, before filling-in the title and track number.
MP3TAG can do automatic tagging but I’ve never used it. I assume it might take longer to find & download the correct data and then I’d still want to check it, and possibly edit-reformat it.
When I rip CDs they get tagged automatically but I still check and sometimes edit.
It might take some time to find and download the album artwork, or scan it. Since a regular scanner is too small, I took a few albums to Kinko’s once and they wouldn’t scan it because it was copyrighted! I ended-up using some photo-stitching software to assemble 4 scans. (I don’t remember what the app was.) A “modern” phone camera might also do a good job.
What took me a LOT of time is when I decided to check/correct the original release year. Sometimes it’s hard to find, especially with a greatest hits or compilation album. Usually I had the CD and the original release may have been on vinyl.
The developer sure knows a lot about MP3s! When I’ve used it I usually just blindly ran the “repair tools”. 
…When I was using it, most of my problems were related to the VBR header which was making the wrong elapsed-time or remaining-time show-up in the player software. (I don’t know what encoder was causing that problem but I’m not having it anymore.)
I tried the options as shown in the screen shot. No change - no metadata in the car.
I tried writing only the IDv1 tag. Again, no change.
(Just to be sure I did it right… I used Remove > Undo > Save to update the tags.)
Questions from above
Okay if remove and manually tag? YES
RE: manual tagging vinyl rips
As I carve up the ripped album side into individual tracks in Audacity, I assign the track names. Audacity uses that to name the file and set the tags when rendering the MP3. The tagging happens for all tracks on the ripped recording automagically.
Re: tagging at album and artist at the album level
I recognize that it’s just track number and title that I’d have to hand-enter. Album and artist are easily updated for all relevant tracks at once.
Re: Album art
I use Media Monkey to manage my MP3 library. It has an album art search feature that I’ve found to be remarkably good. It found several obscure albums I have. It’s good but not perfect: for the 6-disc collection “60 Hits of the 60s” it found the album art for five of the six discs. It can’t find Volume 5.
It’s never easy, is it?
If you’re recording audio from a vinyl record, you CAN NOT expect to transfer the metadata automatically to Audacity. There is none on the LP.
There is an option, when exporting to an MP3 or other type of file to have the metadata screen pop up so that you can fill in the data yourself manually.
You also pull down the metadata screen manually from the menus to add the info and the export
That’s not the issue at all.
I edit the ripped album in Audacity, dividing it into separate tracks. I enter the metadata (artist and album name) manually. I also enter the sequence number for each track. Audacity renders the MP3s using the entered metadata.
The problem is that those MP3s – in spite of having complete metadata as verified by several other writers here – are not picked up in any of the five cars in which I’ve tried this.