Well, I’m not going to reinstall it and go through that trouble when I have an alternative solution, but if you want to investigate:
* nav_menu_item isn’t a hook, it’s a post_type
* I found the reference to updating/deleting menu items in inc/const.cls.php
All I know is that after turning off plugins, this is the one that stopped the problem, which was that each night the menu items were gone. It was probably an interaction with another theme or plugin if your other users aren’t having this issue, but my other plugins are non-optional, so unfortunately this one had to go. (They mostly relate to the Hubble Theme on Envato Market and the plugins built into that. I wouldn’t be surprised if there was a conflict there, because the theme has other coding problems.)
Thinking about it, I’ll update my review to mention this.
