Weird colour (or brightness) change when switching between Parallels (in full screen) and Mac

Hi team,
I'm experiencing a weird colour (or brightness) difference when switching between the Mac side and Parallels desktop in full screen running windows 10.
I've never experienced this before and have recently updated my Parallels installation to the latest minor version of Parallels Desktop 11.

It seems like the entire Parallels machine is "selected" and is blue because it's selected, like when you select text in a text editor on a mac.
I've tried to screenshot the difference, but it doesn't work unfortunately.

Does anybody else have this issue or have any ideas as to why this might be happening?

Thanks in advance for any help.

 

thanks

 

Did you get an answer on this? I'm having the same issue and have done ever since installing on my M1 Mac with Parallels Pro. The update to P18 hasn't fixed it