Window Manager/X issue?

New problem popped up after upgrading packages and I’m not sure how to track it down. Basically, when attempting to log on to my Kodi box locally (at the TV), I get the lightDM greeter for username/password just fine. If I attempt to login to the Ubuntu desktop, the screen blanks for a couple of seconds and then drops right back to the greeter, asking for username/password again (if I enter the wrong pw it gives me an error). If I attempt to login in to the MATE desktop, it loads but at something like 640×480 res on a 1920x1080p display. Everything is giant. I’m guessing the Ubuntu desktop is just dying at that resolution. I can’t load Kodi from MATE, it just dies after a blank screen as well.

From the MATE desktop I have checked Display settings and it says the physical display is at 1920x1080p.

I can login via X2Go remotely and get a perfectly functional desktop so I believe the issue is with the configuration of the TV as monitor but I don’t know where to look from here. I’d appreciate any suggestions and advice!