Whenever you open a group shape in Schematics, it assumes that you have modified it when you close it and forces you to make a decision on it the next time that the catalog is verified. If you don't verify it right away, you may have forgotten why it was opened and choose the wrong disposition.
Quite often a person opens a group shape to check on details or to copy something.
It would be good if the software could check for changes and ask the user if they want to keep the changes (sometimes something is inadvertently changed or changed back) when the sheet is closed. This would be similar to what happens in most programs when they are closed.