Julien provided some helpful hints on examining a cutter in this thread.
If you still have a new, known sharp, similar cutter it might be worth running a small test toolpath back to back between that and the bit you’re suspicious of, you obviously know what chatter and unhappy cutter sound like. I mostly cut birch ply which means only carbide is worth using at all, I’m also a little cheap and use a diamond sharpening card to refresh the flat faces on the chamfer bits a few times before buying a new one.