I am not sure if this is a bug or not.
I am using mp3tag v2.58.
and editing flac files thru the extended tags.
I will select a group of files to edit.
right click and select extended tags.
If I select only one file that has the tag / comment of RippedBy its value of XXX
and I change it to EncodedBy its value XXX it will perform the change.
But if numerous files have RippedBy and different values and I change
it to EncodedBy it deletes the RippedBy and doesn't write the new EncodedBy.
Note there are no new comments added at all.