My custom harvester's PF3000 appears to be freezing for 6-8 seconds, then updating on the screen, then freeze again.  Data is only being logged at those intervals.  I set a new load and after approximately 6 acres the monitor had registered/recorded 0.6 acres. 

Elevator speed is optimum (380-400 rpm).
GPS updates are correct (GGA and VTG messages, once/second)
Battery voltage is 13.0 V.

Card was clean upon start up (32 meg). 

It was operating correctly at the start of the field, then started misbehaving later.

I've not run across this kind of behavior before.  Any ideas?  I can get him a different monitor come Monday, but we'll have lost the data for this field, it appears.