I have the same problem. Although the only odd thing is that the sheet says it is out of date. Everything works normal. I just ignore the message.
There seems to be a difference between updating the sheet and updating individual views. If you forget to hide sketches they will immediately show in all views and after hiding you need to update every view to hide them. Updating the sheet doesn't work here. It did in the past, I guess untill NX8.5.
It would be nice if there is an update everything option. (there probably is, for more then 10 years, I just don't know where it is I am afraid)
I vaguely remember someone having the same problem a while back. I think in their case it had something to do with a drafting sketch (the sketch was out of date or had lost a constraint or similar...).
Sheet 'Out of date' can also happen when the part has sub-parts assembled within and they're in suppressed state. Either delete those 'suppressed & unwanted' sub-parts or load them (also means that it appears in the drawing).