All of them or just one? If you go to the app drawer do they still work from there?
Individual app shortcuts can break easily. Sometimes an update changes something in the app so that the desktop shortcut no longer works, in which case the solution is to remove and replace the shortcut. So if it's one, maybe two of these apps where the shortcut no longer works that would be my guess.
If the apps are all installed but none of these shortcuts works then it's a glitch in your launcher (the app that handles your desktop, and hence the app that manages this folder and the shortcuts it contains). The simplest solution is to recreate the folder then delete the old one.