Check what your paper setting for MPT tray is. Mine was set to cardstock and once I changed it to plain paper the printer was back to autoselect.
Pretty much the same issue here. No matter what we have loaded, all print jobs go to tray 1 no matter what. We have even tried opening the tray and making the jobs force to another tray with no luck. We have completely rese the print system, cleaned out CUPS, set defaults in CUPS and tried to make presets with "auto select" as paper feed optin and it always resets to Tray 1.
Recently the printer is selecting the MPT tray no matter what I print. I have 8.5x11 in Tray3 and 11x17 in tray 2. I havew reset the printer to facotry settings, Updated the firmware and re-installed the latest driver. Cant figure where else to look.