When I set the viewer to fullscreen, I get a flashing X (like an 'exit window' icon) top right in the view screen whenever is is updating. This has always happened but seems (???) to have got worse recently.
Main machine, Windows 10, Nvidia 1080, Spacedesk Driver 0.9.20
Viewer machine, Windows 10, Nvidia 860M, Spacedesk Viewer 0.9.19