If you have Screen Time enabled, and haven't yet added PC Matic to the Always Allowed list, you might want to do so now. In fact, it should be mandatory upon installation. I just discovered that if the feature kicks in when a sub-feature like Downtime or App Limits triggers it, it will prevent the app from running until you return to your Mac, leaving your Mac vulnerable to malware and attacks.
To resolve this issue, you must perform the following steps:
Open "System Preferences" from either the Apple contextual menu, the Dock, Launchpad, or the Applications folder in Finder.
Click "Screen Time" to open the Screen Time preferences.
Click the "Always Allowed" tab.
Click the search bar, and enter "PC Matic".
Check the box next to PC Matic.
If a four-digit passcode is set, you will be prompted to enter it.
The attached image shows what the window looks like when you complete the above steps. After that, you shouldn't encounter anymore issues with Screen Time stopping PC Matic from running.
I hope every end-user of PC Matic for Mac finds this article helpful. I'd hate to see what would happen to other PC Matic users if Screen Time did this to them, too.