I am currently playing on a laptop with a 4k resolution monitor. I can't play the game at that high a resolution so I turn it down to 1920x1080. However, every time the game does an auto save (eg : new cycle) and sometimes even randomly during play, the screen locks briefly, flickers and then resets to 3840x2160. Making the game run at a very low fps. I have to then go back to settings and return it to 1920x1080. The game always starts at 3840x2160 regardless of what I had left it when quitting.
If I play with an external 1080p monitor, the game remains at that resolution the entire time.
Set to lower resolution than native resolution
Play until game auto-saves (until a new cycle begins)
Screen flickers and native resolution is set automatically