So it’s a bug in Cubase 8.5?
Edit: Nevermind, I found a solution, or at least some kind of workaround! After hours of searching on countless forums I found that activating the mouse trail and switching to the Inverted Scheme in the Mouse-Options of Windows stops the flickering. It looks a bit fuzzy, but at least I get no Audio Dropouts anymore. Maybe I’ll find a better solution in the future, but for now this has to do the job!