Submitted an issue now - I'll see if it is written correctly and if they are open to this.
The fix was implemented and the update already released and according to a quick test, it works! Wow!
So I can now use mp3tag for the complete workflow, now I just have to scrape the folder names to put the sequence numbers into the GRP tags, but that is a different story. Thanks to all of you for your help!
Cantello, I'm very happy for you, I was following your writings...
Wow, the update is very fast...
A big thank you to LyricsLover, for the help he gave you, he believed more in an update, to solve the problem, than to write a program...
A story that ends well... 