Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
Unfortunately, Navco, the maker of the head unit. Hasnt provided any software or firmware updates for download.
I believe what you are experiencing is any issue with the headunit itself, and not the garmin app inside it.
Let me ask you this, is the screen calibration off regardless of what function or feature you use on the infotainment head unit?