[whpalmer4]

I'd give the support ninjas a call in the morning and see if they can find some clues as to what happened. OmniFocus writes to the disk so often that it is difficult to imagine how it could have stopped doing so for an afternoon without showing other signs of distress. There's absolutely no possibility that you were operating on a backup file instead of your main database? That would produce the same observed behavior...

If you do have cause to send out another warning in the future, it would be helpful to know exactly which version you're running!