Have powered-off all devices for at least 10 minutes and replaced the HDMI cable to a branded cable (loglink) that I have previously used with my Raspberry without problems.
I cannot watch telly… I’ll report later whether this solved the problem.
With that said, I just saw that someone else experienced the “Randomly blue/green tinted picture - #44 by gerifoka”-problem with a Philips TV and also experienced problems with HDMI CEC that “stops randomly, like instantly after boot or after 5-10 minutes”. Maybe these problems are connected?
Best, M