applicationsfindericonmacosmojave
Notice the clock or piece-of-pie icons next to 3 of the apps in this screenshot of the Finder. The icon has been there for two days. All three apps work; I have used each of them.
➥ What does that icon mean?
➥ Is it a problem? What can I do to fix it?
Using macOS Mojave 10.14.5 on a Mac mini (2018).
It's a glitch, where the grey overlay that appears on top of an app when you tap it is retained when you exit the app.
You can remove it by interacting with the app icon in some way, whether that be swiping between pages starting with your finger on the app, or simply tapping the icon.
It appears to be fixed in the dev build of iOS 7.1 :)
The icon means that the calendar is being shared. Click the icon for details:
Best Answer
Bug
Apparently, the icons where caused by an innocuous bug.
After restarting the Mac mini, the icons were gone.