I'm glad you got it resolved.

The host said they were doing a migration, but that should not have caused the issue. During the migration the site was timing out. I don't know if you've heard of similar experiences.

I still do not have complete answers, but am digging and will let you know if we find the root cause.

Remember as long as you make regular backups of your db and forum files too, you are covered no matter what happens. All you have to do in the worst case scanario is to roll back to your most recent backup.