aegis

I have had this radio for many years and have never had a problem until recently. One aileron servo is plugged into channel 2 and the other into channel 6 (the channel for flaps). When I adjust either my sub-trim or EPA for channel 2 it also changes channel 6. It doesn't matter which flap position the flap switch is set to or where I have the flap POT set. When I try to adjust the sub-trim or EPA for channel 6 nothing happens. I sent it in for service, but it still does the exact same thing. (I can't read on the work order what exactly was done). Any idea what is causing this? Thanks.

Dan