I am going to take a wild guess and say it has got a burr under its saddle. We have owned two PF3000's for several years and on maybe two or three occasions they have gotten to the point they were doing funny things - different things each time brought about by different reasons. In each case in talking to tech support they had us "newbox" the console and the problem went away. I would call tech support but one thing I would do before doing so (in case they talk you through the newbox procedure) is go in and write down all your settings on the various setup screens and calibration numbers. You can take a current data card and it will restore all these settings to like you had them but "just in case" I like a hand written copy of the settings and numbers. It is hard to remember the way all that stuff is set up and takes some time to wade back through the manual and figure it out if something goes wrong in restoring the information - there was one occasion I wished we had written it down. Just a word to the wise.

One such calibration number that we have somehow lost a couple of times is the cal number for the ground speed from the tires. We have the speed set to GPS but if you loose GPS signal it reverts to the backup ground speed and if it is not calibrated you will get some really wild yield spikes every time the GPS drops out. Just an example of why we like to have a written copy of these settings - we write them down on a sheet of paper and put them in the AgLeader manual so we will not loose them - "just in case". Voice of experience talking. 

I think tech support can talk you through and figure our the problem. I have had good luck with them.

John