When you use the Windows client right-click context menu and use the "Clear invalid files" feature on a folder, it does not detect that files no longer exist in their location (they could be moved, renamed or deleted). This really should be noticed by this check, but instead, it says "No invalid files found" and any such invalid files will remain listed in the client.
I can only assume it works the same on Mac, but I haven't tested myself.
EDIT: The intention was to post this in the "Other" section and not under Quest 1 & 2. Sorry.