My 120v plug for my fridge is mounted on the floor near the bottom exterior vent panel. It has to be GFCI due to being mounted in that location, just like all of my other 120V plugs that are located in basement compartments.
My converter is also on the GFCI circuit, as it's mounted on the floor under my drawers in the kitchen. When the GFCI is tripped, no more charge to the batts. No charge to the batts means that the voltage is going do drop on the batts, depending on how much draw there is on them.
Whether on LP or 120V operation, your fridge will still need 12VDC to operate the control board.
So it's possible that your batt level dropped to the point where the control board didn't have enough juice, and you got the "CHECK" light.
Complex things, these movable houses
😉Jim
2005 Pace Arrow 36D
Very Understanding Wife
1 Boxer 😞
3 Maine Coon cats