I believe the floor joists run the length of the camper, rather than crossways.
There is only a thin layer of "plywood" over the joists and styrofoam, so is easy to crush it over time. The styrofoam is firm at first, but repeated loads from foot traffic eventually crush it, and then the thin plywood just caves in.
Seems to be a common problem, and why we never wear shoes in or lightweight. It has the same floor construction, although I think the "plywood" is a little bit thicker. I am not sure what year they made that change.
This is one of the sacrifices one makes when buying a lightweight camper, although it is getting more common as the manufacturer looks for ways to cut costs.