When I took off the truck camper this weekend my wife looked under the camper and noticed this! My truck bed has a very heavy duty truck bed mat and nothing was between it and the camper when...
I had the exact same thing happen on my Arctic Fox 990 from leaving a small piece of 3/4 in plywood in the bed. I felt sick about it but after contacting my insurance company, I felt better that they would cover the repair. The RV dealer near me placed a 3/8th plywood sheet over the entire bottom. It was coated in a black finish like undercoating. It is now much stronger than the flimsy sheathing that was the original bottom and looks like it's a factory finish.