last month i`ve seen the same problem with another pool where i have some miners, the pool operator said that blockchain isn`t always right
Blockexplorer also links #286209 to Slush, and the payout address is correct on both Blockexplorer and Blockchain, so either they are both right or both wrong.
No doubt it will get fixed in due course.
it seems your right block #286126 (which slush`s solved) was payed to the same BTC adress as block #286209