I was never able to figure it out. It may been ops cache related (notoriously unstable). In the end, I migrated the blog to ZippyKid (had been planning to do that anyway) and haven’t had any problems. Good luck!
I have not. What’s the logic behind reducing of menu items? Is something timing out? Or overflowing? And why would it work for tens of thousands of hits, and then fail every hit until a reboot?