No expert here. First thing I would do is go to the Uavionix page and make sure you have all the software updates properly installed. I had a very similar problem when I first installed my Echo UAT as you describe. I thought I had everything updated, but in actuality I did not. Fortunately I had my 6A at OSH a couple years ago when I was experiencing the problem and one of the Uavionix staff actually came out to my airplane and got things properly updated for me. I felt both very grateful and pretty humbled.
Check those updates, even if you think you have them installed.