Nico - seeing as you've said you won't be looking at this bug any more (or words to that effect), isn't it about time WGT thought about changing how it's played, making it a single player competition, and taking it away from coin rooms?!?
Failing that (and I'm sure you'll say single player isn't an option, although I'm pretty sure there's no good reson for it), what have you done to try replicate the problem? Have you spoken to players that have had the issue (there are many hundreds to choose from!)? What about getting a few members together who are willing to partake in a test, getting one of a pair to forfeit and see what happens. Get them forfeiting in different ways to see what difference it makes. You could do it with your own staff, but quite frankly I'm not convinced they would have the knowhow to do it alone. I'm sure at the end of the test (if done properly!) you will be able to determine the cause, and then hopefully find a fix for it.