M4a file not loading tags

Something is going wrong.
m4a files are losing tags. When I am writing specific fields in mp3tag.
here is a example. Mac finder is showing the album artwork, music app is also showing artwork (we might claim its coming from library). artwork is visible in finder.

but mp3tag do not show the artwork.

Every folder, with m4a/aac files, after the first three files, songs are losing artwork and tags.

attaching the same song for testing.

I can see that the sample file has no cover.
I can add any odd picture as cover ...
So what is the problem?
So it could be that your player still shows a picture from the folder and not the one from the metadata.
Strangely enough, you have a tag field _PATH in the file...
Also, I find it strange that the field ALBUMARTIST is not filled - as this is usually the data that is used for grouping files of an album together.