No offence, but after all the issues the MMM has had and all the work Patrick/CC have done to get them up to scratch, I *seriously* doubt that Patrick's about to let thousands of MMM V3s leave the factory if they apparently have such an obvious flaw. If there actually was a problem, there's no way he'd be daft enough to say there wasn't after they've tested the issue to death.
Besides, electricity will always take the path of least resistance. The MMM has 0.0003 ohms per phase resistance, which is probably considerably lower than that of the aluminium heatsink (even with the anodizing worn away), so won't be an issue. What happened to your friend's battery?
Sorry, I'm not trying to get on your case! It's just that Patrick has explained and stated that this isn't a problem and has never denied any of the issues that presented themselves in the past...so I just think we should perhaps (IMO) take his word on this one. He's the electronic engineer.