Hi Guys, I don't know if this will help (reading your tags) but have you tried VLC. I didn't know how powerful at reading tags until about 3 days ago. Just a thought.
I found the tagging powers of VLC somewhat limited looking at this thread:
VLC has a fixed set of fields that are displayed:
(from my file used here)
I'm not aware of any easy way to change this.
Other tags are visible in the second tab
(in a less obvious order):
I would recommend VLC as a very good music (and video) player.
But I would not recommend it as "alternative tagger" for tagging your files, due to the very limited number of editable fields (first screenshot).
Yes, you are absolutely correct "Not an alternative tagger" But a viewer was all I was suggesting.
I agree — the OP did not suggest to use VLC for tagging, but instead suggested to use VLC for reading tags of a problematic file as discussed in the original topic before his answer was split to a separate topic by moderation.
I'm changing the topic title accordingly to avoid further discussion in this direction.
Sorry for my misunderstanding - probably I was too biassed as in many threads "reading" tags is used as synonym to "edit" tags.
No apology needed.... 
OK, let's go back to the original issue: the topic you originally posted in concerns a specific invalid tag in an MP4 file. We've already had a productive back and forth and arrived at a concrete solution.
Unless you believe the solution is incomplete or have a genuinely better alternative, I kindly ask that you avoid adding new solutions to existing topics. However, if you’ve carefully read and understood the existing discussion — and you believe your input contributes to resolving the issue — please go ahead and ensure that you've tested and validated your suggestion before commenting.