This is directed at the team, since nobody else will be able to help.
The key I took out for StackMobile is behaving strangely. I make a few requests, and then the limit resets to 0. (By limit, I'm referring to the X-RateLimit-whatever-its-called header.)
Update: it's not the limit (10000) that's getting reset, it's the number of requests remaining. It starts at 9999 and every few requests, it resets to 9999.