change of behavior fo the color picker recently

hello 

Weird new thing that is not working as before since recently 

I'm used of using the color picker to get the color from the UI background (the grey area around artobard) 
I use that to color masking elements around the artboards. #383838 in my case

- Since recently, the color picker does not get the info, and I get a "?" in the fill color  field

(color picker properties are set to get every type of info (appearance, fill etc..) 

Is this a bug on recent versions ? I'm in 27.8.1