It's not going to happen. The fronts carry more than the back, and one of the backs will always come off the ground leaving three to carry the load. I actually bend one back leg and the camper was just fine on three legs until I bought and installed a replacement.
When I was unloading off the truck as soon as I saw one off the ground I would stop the four and just run the one until it was solidly down again. It's a process, and after a while it just becomes automatic to re-adjust occasionally.
Mike
2012 Winnebago Impulse Silver 26QP
2005 16.6 Double Eagle
2018 Jeep Wrangler JK
previously Snowbird Campers,
Triple E Motorhome and Fifth Wheel