I am not sure if this is a bug, I think it is intermittent. When I take a screen capture using the built in tool, my image is captured with darker colors than the original as you can see the image below. I tried restarting BT, but still no solution.
Yes, you are right. I use BetterDisplay, and I noticed that my external display has lower brightness, once I increased it 100% the captured image retained the bright color. interesting, and thank you for that, but why is this happening? a capture is a capture!