Pending at undo "Remove tag" operation

When I correct MP3s, tagged by MP3Tag including Arts, via MP3GAIN, APE-Tags are created by MP3GAIN and shown by MP3Tag. When I remove these Tags via MP3Tag "Remove Tags" and try to restore the combination ID3v2.3 (ID3v1 ID3v2.3) for a whole CD via "Undo", MP3Tag is pending. When I do the same procedure for a single item I have no problem at all.
I assume a "stack overflow" or a similiar problem in MP3Tag.

The question would be: how do you do that?
Here is a way with which you can remove the APE tags without the "Undo" function:

And why MP3tag is unresponsive ... could be that the files are locked by another program ... A stack overflow would probably lead to real crash including error log.

There was also a problem with Acronis Active Protection recently. Maybe related or anything running with similar side effects?

I will try to resolve the freeze - exactly according your proposal. I will give you feedback about the success/unseccess. Thabks for the quick support! Regards from Karlsruhe, Achim