Has anyone else noticed it? It was happening in NB 21 as well, maybe before that, but I don't know exactly how to reproduce it because it doesn't happen every time. Basically select a block of lines and hit delete, then cursor up and down just bounce back to the line you were on. Cursor left/right do something weird too, but if you hold them down you can sort of see it making progress. In both cases it acts kind of like there is still a selection going on the way you see the line highlight.
Scott