Go to options for reading, removing and saving tour tags.
Read: Tick all tag types.
Remove: Tick everything except v2.3
Save: Just tick v2.3.
Select one problem file to test and right click>Remove tag. Dont panic it only removes everything except v2.3 you have set in the options.
Then ctrl+S to save the tag.
Also use a program called mp3val to scan your mp3 and fix there integrety.