I have had issues occasionally and at apparently random where my displays will not turn off after the 15 minutes as specified in the Energy Saver control panel. I have it set that the displays go off but the computer does not go to sleep otherwise. I have isolated it to Parallels by shutting off all other applications from running and if Parallels is running it will not allows displays to go off after the allotted time. As soon as I quite the VM and Parallels they go off right on schedule. Hardware is a 2018 Mac Mini, 32GB RAM with the i7 3.2 6-core running Catalina 10.15.1. Parallels is 15.1.1, (47117) but this has occurred with earlier builds of 15. I have reinstalled Parallels Tools and will see if that clears it up but I am pretty sure that had been done after the last upgrade. I don't recall ever having this issue prior to Parallels 15 or Catalina. Any ideas?