M1 Pro Font Smoothing with External (lid closed/open)

[Grohowiak]

Weird stuff happened Today.
Since I got the Mac everything looked great when connected to my 38" Dell but Today smoothing started to change when I open/close the lid.
I attached a video. At 3 seconds I close the lid and at around 6 I open it again and you can see that aliasing / smoothing changes.
I wouldn't care for most part but I'm getting a much better performance in apps like blender with lid open for some reason.

Any ideas?

**sorry for shaky footage. Had to use phone. Screen capture stops recording when I open / close the lid.

 

[koyeung]

Would it be caused by the ambient light sensor? e.g. True Tone may change the screen a little bit, depends on ambient light.

 

[Grohowiak]

Would it be caused by the ambient light sensor? e.g. True Tone may change the screen a little bit, depends on ambient light.

I tried that option and everything else I could find but no difference.
I'm perplexed.