It's not doing what it's supposed to. For example I create one that's supposed to set up Priority Only from 5:30am to 7:30am. At 8:10 am the phone is still in Priority Only mode. Yet it worked as it should for months. Now it doesn't.
I reboot daily, so that's not it. I don't allow very many apps to run in the background if they're not needed, so I don't think that's it. The problem is just too inconsistent to fully vet out.