Because one of them is on the wrong fork, apparently, or displays its orphans as mined blocks. You can know which one it is when you do not receive payment.
XRamPool is on the working fork.
If this pool really wanted to, it could fork the blockchain though
Then it would have the working fork.
3026 was just mined by XRamPool, its a valid block. MMCPool says that it mined it as well.
Could this be considered false advertising?