Well... the AvCsMgr service is the main Unity process so the CPU would spike if we were processing lots of calls...
The most likely thing I can think of here is there's a memory leak and it's creeping up over time and hitting your swap file at a certain point. Check the processes memory use... if it's sneaking up there over time report it to our support folks. It should stabalize after a couple of days of normal use, if it continues to climb, that's not normal.
