I noticed an increase of orphans last night (europe9), too.
Orphans are part of the protocol and p2pool create orphans as part of the work distribution, as orphan shares are counted also. Orphan shares do not mean oprhan blocks.
I think the percentage of orphan shares increase, when larger changes in the p2pool clout happen, e.g new pool nodes join the cloud or two clouds merge together.
So we should wait several hours and see, if the orphan rate goes back to normal.
Also if one cloud node has many miners connected and therefore has a high hash rate, the number of orphans increase on low hash rate p2pool nodes, as these nodes can’t produce shares fast enough to get them accepted by the p2pool cloud.
The last reason for orphans is a large network delay for one p2pool node.