The stringers are there, but one of them seems to have split open from foam expanding in it. The other two pics I pulled show the stringers and they do look like the adhesive was used to glue the deck on. The creamy wavy looking stuff on top of the stringers looks like the adhesive. If so, then they simply built the liner with too small of a core to handle the span between the stringers. Well that and they forgot the lateral supports.
The rest of the pics are terrible. Man I sure hope you guys get this worked out.
The split open stringer
the other stringers... (the tall red things)