Active Header Height Control Problem

We have a 2008 9770 with a 2012 635D header, we had to replace the main wiring harness on the LHS of the machine to get all the controls on the header to work (including the dual zone float). I was hoping that would also fix this issue but no luck. The Active Header Height control seems to work normally except that, the header will slowly rise up about 6 inches or so and then suddenly drop back down to the setpoint height. I've tried equalizing the float system and calibrating everything but it still happens. Any ideas?

Active Header Height Control Problem