I get this problem with R99 and R100. If I take my very basic app, rotate it a few times, I then get a black blank screen, and have to reload.
I can reproduce on ipad2 and iphone4
It happens after 2 or three switches of orientation.
My app uses scale with letter box, and just diplays some sprites. I made a blank project with nothing but a backgroud image, and get the same problem.
This is pretty serious.