It depends on the amount of memory available. If there isn't much left, the screen will close and you have to get it from drafts today.
Discussion
The latest ~3 versions are crashing much lot regularly on my phone, which us, admittedly, an oddball setup, but, it's still a pretty high end phone with 12gb of ram and plenty of space left.
Android will kill anything when it reaches 512mb. So, being high end doesn't change much :(.
Does it happen Everytime you try to close a draft or just here and there?
Every time I am working on a new note. It doesn't seem to happen when I'm writing a reply to another note, though. That's what stood out to me.