Yeah, that'd be an interesting one to know.
Oh - my bet as to why they've not reverted to an older, functioning version? They don't have one. Doesn't matter if it is a SQL issue, session issue, or page coding issue, it should have already been fixed if they had a working version. My bet is the shop that coded it doen't have good QA and testing procedures.
If one of my systems had a problem like that, airplanes might fall out of the sky...seriously. That's as far as I'm willing to tell what I do...