I reported the following in the 3.0.0 feedback/bug thread:
This just happened again in 3.1.1, iPad 3/iOS 7, normal color mode.
When I've called up the handwriting recognizer from within a dictionary, the writing input area was entirely black. I could write in the area and it appeared to recognize my writing (I think, I'm recalling from memory), but I couldn't see what I was writing.
This just happened again in 3.1.1, iPad 3/iOS 7, normal color mode.