High Sierra does not provide video signal

After upgrading from El Capitan to High Sierra my mac mini doesn't provide video signal to my television after boot-up.

Fortunately i had screensharing enabled which allows me to access the mac from my mbp.

After connecting with my mbp I can trigger the mac to output video by setting screen rotation to any value.

After reverting to 0 degree rotation i can use the mac again as it should.

That is, for as long as the mbp is connected by a screen sharing session.

High Sierra cuts the video output again once the screen sharing is terminated.

I invite anybody with ideas how to solve this to reply.

Bart

hardware

mac mini (mid 2011)

hdmi 1.4 + ethernet cable connected

LG model OLED55C7V

installed extra software

VLC player

Audirvana 3 (3.1.4)