Huh. We shouldn't be cross submitting shares. However if our connections lag out we leave your pool. And then come back when it delags. So giving us bad connections causes a lot of wounded thrashing.
Cross submitting shares shouldn't happen though... I'll check.
As always though using a proper algorithm would be nice instead of messing with the hoppers.
Ive only noticed the high stales (false submits?) for bitclockers, so I highly doubt its the hopper at fault since the whole lot of other sites would have had similar instances.