I have another flash-related problem with my N900 after updating to PR 1.3.
I am only able to watch youtube videos in 240p. If I change to any higher resolution I get a lot of artifacts in the image in form of vertical lines across the image. At the moment I change to 240p the problem is gone. I guess I can live with 240p youtube but it is a big problem for videos where I can't lower the resolution. The problem persists even with Tweak-flash uninstalled.

Anyone else out there?