I don't know anything about anything but 2 thoughts come to mind. 1) Is there anything pushing against the lift gate that might cause the latch(es) to jam? And 2) (sort of along the same lines) are both rubber bumpers (attached to the bottom corners of the lift gate) intact? If one is missing, it might cause the lift gate to become crooked. I'm thinking maybe, if the latch(es) are full of dirty grease (or no grease at all), it might not take much to keep them from releasing. A little bit of cold might be the final trigger.