Yes, there's a bug that Smoovius reported on the Litecoin P2Pool, which would also apply to the Bitcoin one. P2Pool's memory usage can grow without bound after a fork like this if you maintain connections to people mining on both forks. P2Pool is unable to forget about the children of the root node that connects the two forks, due to that operation simply not being implemented. (I assumed that one fork would always lose eventually, resulting in a linear chain whose last node can be forgotten about.)

Anyway, it's fixed in git, and after some more testing, I'll release v9 and the switchover will be triggered when v9 becomes popular. Restarting P2Pool after the switch would have been enough to fix this, but many people don't have something auto-restarting P2Pool if it crashes or even check up on it often.

The switchover happened on the Litecoin P2Pool about a week ago, and went flawlessly other than this issue.