Loose issues after 2021 upgrade

[JLGF1]

After upgrading, IMatch 2021 tells me there is a meta-data issue with 3 (old) files, but is a bit cryptic on what the issue is.

[Mario]

Point the mouse at the blue info circle for general info.

Click the arrow to open the files in a result window.
Do they show a yellow warning icon? Yes => point the mouse at the warning icon to get more info about the problem.
Write the files back if they show the write-back icon.
Else select the files, press Shift+Ctrl+F5 and then reload metadata