Unlock secreen is not coming after pressing the power button

During the last weeks I am often experiencing the following bug:

1. I shortly press the power button to lock the screen phone.
2. The screen turns black as expected.
3. I few minutes later I press the power button again so that I can unlock the screen entering my pin.
4. The screen remains black and I cannot interact with the phone anymore.

I have seen that when I press the button again (step 3), the following message is shown by journalctl when connecting via ssh:

feb 20 18:39:38 hostname phoc[751]: [types/output/output.c:656] Basic output test failed for DSI-1
feb 20 18:39:38 hostname phoc[751]: Could not set output enabled state to 0