1968 shasta loflyte

Briefly from your description, I would guess that what is actually happening is, the wall framing in the front wall is collapsing due to wood rot. This happens after years and years of small amounts of water leakage into the insides of the walls, where it is largely not detectable... The weight of the cabin presses down onto the frame, and makes it appear as though the tongue is actually lifting. It will first slump, creating a "frown" look in the skin across the front, eventually tearing into the skin at the point of contact with the tongue frame.