I saw this issue mentioned a few times and I've experienced it many times. This usually results in a complete document loss (if its the first save) and I would call this a criticial bug that should have already been addressed.
When I try to save a new document and inside the 'save as' dialogue box right click for a new folder the entire CC app crashes. This happens both in InDesign and Illustrator. I am running windows 10 with updated cloud applications.
This doesn't occur every time but is rather sporadic.
Please have this issue looked at.
The next time you see the crash, please share the crash dump with us.
I have sent you the steps in you Inbox.