OK this is my theory, looking at my potcoind logs at around 11:20GMT we have 30 blocks all accepted within 3 mins, the result of that knocked the diff way up ..... and we are still waiting for it to recover.
Blocks are now being acepted again, my pool (
https://pot.suremine.com ) has just processed a block. I think the difficulty may rise again as I saw a whole bunch of blocks get processed at roughly the same time, but hopefully things should start settling down again.
A multipool may have jumped onto Pot briefly, Solved a bunch of a blocks and jumped off when KGW kicked in. That would cause the difficulty to jump up briefly
