Ahh... this sort of thing happens to both Bigfoot and Northern Lite campers - the area you have circled is part of what folks call the "T-Wall".
Forgetting for the moment that fiberglass with the proper thickness and properly saturated with resin all the way through (it is my understanding that both companies "blow" fiberglass and spray resin into/on the insides of their molds - not an exacting method) is "HARD like a boat hull" and would rather BREAK or CRACK rather than "bubble" or "bulge", both Bigfoot and Northern Lite at times (~1/2 dozen NL's have reported the issue over the years) seem to have difficulty getting enough fiberglass+resin in this critical vertical section of their molds resulting in just that - ether what owners describe as a "bulge" or "bubble" in the front vertical wall of the lower section of their campers!
There have been a number of different DIY "fixes" or "work-a-rounds" for this issue posted in the various forums over the years generally involving removal of the 'pass through window' and most/all that is directly behind the wall and ether injecting resin or glue and/or adding plywood/metal sheet and/or using clamps through the window to squeeze both sides until the resin/glue cures and reassembling the inside of the camper and reinstalling the window.
One owner was able to snake a tube to dispense resin/glue into the wall section (between the fiberglass and insulation) and was able to clamp the bulge so that it was flat and then upon removal of the clamp was able to reassemble without to much of a tear down disassembly of that area of the inside of the camper.
I think one owner was still within their structural warranty period and took their camper to the factory for repair.
Thankfully both companies are generally good at fiberglass+resin coating their molds and out of the all the units ether company has shipped over the years there have not been a large number of campers having this failure.
- Mark0
(owner of a 2014 NL 9.6)
