I have noticed that when switching pages note offs don't seem to be sent at the moment the page switches but when the note on the stopped page would have expired. I have been using notes that are 8 bars long to trigger samples and switching 'too early'. Not sure if this is a bug or as it should be.
I've done a bit of programming work in this area for v6 so I know the behavior pretty well. Yes, this is how it's supposed to work, except that there is a maximum note length of something like 4 bars. That may be what you're running into. In v6 Solo Recording view, I made some enhancements for recording long ambient pads/drones. One of the features was to automatically add the note off to any held notes when the loop ends, or when stop is pressed. I noticed while programming and testing that notes will end automatically if they hit their max length. In the code this is tracked with short notes and long notes, each with a multiplication factor.