the way i understood orphans is that the pool forfeits the earnings for that block. 

orphans are blocks that the pool solves, submits to the network, the network initially appears to accept them but then for some reason on another it decides to reject them - usually because some other pool solved the same block a millisecond faster, but the blockchain didn't catch up and register it in time etc.

so, not supposed to get paid for them. 

ddos cause them sometimes, or it's possible that a huge pool is ravaging a small network by overwhelming it etc, etc...

so, orphans happen, especially in a smaller pool.  but when there's barely any for weeks and then you see a lot of them on the same day, usually something is misfiring somewhere between the network and the pool.