@enderwiggin: You said, it happens after syncing with your mac. Is it possible, that your OF database is huge? Maybe the sandbox is getting backup into trouble if the application data is beyond whatever.
I know, that sounds pretty stupid... but as I am developer and qa guy too, I've seen a lot of stupid errors and made even more myself. It's just an idea, the problem sounds pretty strange to me.
Or did you give it a try with a different phone (to be sure, it's not a hardware specific problem)?
P.S.: If the apple guy knows, what he's talking about, there should be someone telling apple what all the sandboxing stuff is about. As far as I understood it (from the apple specs), it should be impossible for any application to corrupt others or the OS itself. For every application, it looks feels and works like the application is the only one on the phone or in the hole wide world.