Mp3Tag fails to read ID3 v.2.3

We are not talking about deleting the metadata, we are talking about undo the gain-changes done by MP3Gain. If you delete the metadata you will not be able to change the gain-changes autamtically.

I assume that MP3Gain makes use of these "memory values" in order to revert the physical changes in the modified Global-Gain-Field within each physical mp3-frame.