I expect this is on all variants, but I have the issue specificaly on Kubuntu 11.10.
Flash applications causes terrible screen distortion, flickering, and redraw problems. It is so bad that, switching to another virtual desktop and working in a VirtualBox system is also affected. I'll try to get a screenshot!
As soon as the browser tab with the affected flash application is closed, the screen recovers.
It seems to happen for all flash apps.
I suspect it is related to the latest Flash-for-linux garbage-ware.
Any ideas how to get it working again? Go back to a manual instaled flash player? Lock it's version? A PPA somewhere with a working flash player?
Searching for problems with flash brings up many old reports, but I'm not hitting the right search terms to find a solution to this new mess, even though I suspect many are facing something similar right now!