Gen 2 MFD (nav) - Vertical Lines on Nav screen...

I have what others have run into... Nav version MFD works fine for most buttons on the left but the buttons on the right relating to Nav just bring up either a blank (dark) screen, or a dark screen with vertical white lines.
Initially, I had communication messages and diagnostic errors regarding communication with the nav unit. I reflowed the 60 pin connector between circuit boards and now I have no communication issues - at least detectable by the diagnostic mode. But I still have the same blank screen or vertical lines when trying to access nav. When bench testing the MFD, it powers up fine and when I select the nav functions, it just says the nav is disconnected but the screen looks fine. Others with similar symptoms have mentioned replacing the MFD solved it but I haven't heard of anyone actually finding the culprit. My NAV unit under the left seat has power and connectors are tight. NAV CD seems fine. I just recently replaced the capacitors in my dead CM which fixed that. I'm wondering if the caps in the MFD would cause these symptoms?

Fairly new 12v battery.
All fuses good.
Reset nav system several times (12v disconnect)
It's a new car to me so I don't know the history of this specific problem with this MFD.
MFD model 86110-47220 (bluetooth)

I will check grounds for the NAV unit in case there is an issue there.

Any insight to a specific fix for these symptoms would be much appreciated.

 

When I wrote "most buttons on left" work, there are a couple screens that bring up a blank screen. They are secondary screens under the maintenance section and another one that I can't remember. Maybe those issues indicate more than just the Nav system? Could I have missed some pins on that 60 pin connector?