The case of the missing comments

So this weird thing happened over the weekend. Somehow, Monday morning, none of my bloggers were able to post to any of the blogs I host with Movable Type. And MT was acting strange in other ways. It listed each of my hosted blogs as having no comments at all. Actually, it didn’t list 0 comments it just left the space where the number would appear in the blog listing on the main MT blank, and for each blog it didn’t list comments at all above the list of the last five incoming pings.
At the same time, if you clicked on a comment or comment author you got an error page.
The problem was maddening and I couldn’t figure out what had caused it. Had I deleted all the comments somehow in an overzealous attack of spam-cleaning? No, because then MT would just know there were no comments and that would be that. Instead MT expected there to be comments but wasn’t able to access them.
Had someone hacked into my mySQL database? It seemed unlikely, but I still have no idea what caused the problem.
Stranger still, sometime today I got a spam comment notification which tipped me off to the fact that my comments were working fine again. Back in the MT backend all the comments are listed as they used to be, so whatever the problem was it has gone away. This is cold comfort as I’d rather know what the problem was so I could know whether to expect it to crop up again.
Then this evening I was reading blogs in my newsreader and I noticed an entry at Adam Felbers’ Fanatical Apathy (Vast Conspiracy):

I don’t know, folks, I just don’t know. But it seems as though all your fine comments are now inaccessible. I’m not sure if this is a Movable Type glitch or the result of a huge covert operation perpetrated by a cabal of shadowy men determined to silence me.
I’d prefer the latter, of course. Who wouldn’t? But it’s probably just a bug.
Come to think of it, it’s not ME they’re silencing right now. It’s YOU. I always knew you were untrustworthy. Sneaky. No wonder those dark forces want to keep you quiet.

Curiouser and curiouser. Sounds like the same problem I was having. A time-sensitive bug in MT?
Anyone else have this problem? I’d love to know what caused it.
It was strangely frustrating losing control of all my blogs. I felt truly stymied and helpless. I’m still disconcerted. Now I’m off to backup the database….