FYI, I believe I've experienced this issue on both Linux & Mac OSX.
I've moved my P2Pool/bitcoind node (rossbennetts.com:9332) from Ubuntu to OSX since my P2Pool instability began and they both seem to become flaky after a few hours of uptime (since ~v0.10.something). I've tried both core and xt.
Two other bitcoin nodes, one connected to electrum-server and one standalone, seem fine.