I heard recently Slush pool hashrate jumped from 6 PH/s to 9 PH/s, maybe this is your answer.
Too damn right! And they had a period about 7 hours back (just before that massive jump) when my rigs were not registering any shares. I had them pointing at slush and treble-checked that they were hashing, but nothing showed up on the pool!
front end has little to do with backend
Did not change the fact that
payout kept diminishing .... anyway, while investigating the probable cause, I switched my rigs to a P2Pool node then after a while noticed the jump in their hash-rate, I think I'll stay away from slush for a while unless their luck improves substantially due to the increased hashing.