@sdetweil Thanks for the suggestion. You were right. It was a Home Assistant automation going haywire. The automation switched off the screen via MMM-remote-control. On top of that somehow the “blank screen” option in the Pi settings was turned on again (no clue why, maybe after the last update).

Anyhow I now tamed the automation and turned off the blank screen again and now it seems to be working normally again

Wow, I am blown away by the many responses. Thanks so much guys!

Especially thanks @sdetweil, for pointing me in the right direction with MMM-Remote-Control. That module is absolutely awesome. I now figured out the whole thing, so here it is if anyone likes to know:

First I installed https://github.com/Jopyth/MMM-Remote-Control
You need to use the Rest API requests as in the instructions in the module

I found this for HA: https://community.home-assistant.io/t/controlling-magicmirror2-from-ha/138527

So I need to add each rest api call I want to automate as service in HA. Then I can trigger the service i.e. shutdown in my “leave house” and “night mode” automations.

There are then 2 steps:

1. shutting down the Pi via the service/rest api call
2. wait a min or two and then kill the power to the pi by switching of the outlet which I can do also in the automation.

When the state change is triggered (e.g. I return home or I start moving in the house in the morning) then the automation just turns the outlet back on and the Pi will boot.

@hesspoint Update: There is actually a custom HA integration that is awesome: https://github.com/sindrebroch/ha-magicmirror

So I switched form the REST API to that integration and it is even better