has no visible fasteners on the inside. I'm sure mine was factory. I suspect yours was added later. That's why I asked about the inside hardware. There was a post about another Bigfoot
17 with exactly the same problem and the photos they posted they had some hardware inside just like you described. I'm guessing that factory installed awnings were attached to the trailer with some sort of backing plate between the fiberglass and insulation and the "added on later" ones were attached without the backer. I suspect they just drilled thru the fiberglass and insulation and paneling. The construction of the Bigfoot is like a sandwich, and after a few years the insulation collapsed and everything loosened up. You could eliminate the awning and remove all the hardware, then fix the damaged structure patch the fiberglass. Another option would be to remove a substantial amount of interior cabinetry and headliner then reseal and reattach the awning with a substantial backing on the inside of the fiberglass. Either way you have a major repair project. This is just a guess on my part and I may be wrong ( I hope I am ) but tearing the trailer apart will be the only way to know for sure.
The thread about the similar situation on a Bigfoot 17 was started by someone who discovered the issue prior to purchase. I don't believe there was any information about repair. I believe the buyer backed away from the deal. I'll see if I can find the old thread. You might have purchased the very same trailer. Please don't "kill the messenger" . There is nothing I would like better than to have you dig into this and tell me I'm wong.