I am having what may be exact same problem with my 2006 Adirondack 27DSL-FK trailer. First noticed it this spring.
Floor in front of the stove is soft. Cannot find any source of leakage from water heater (which is in the area) or sink. Only potential source I could find was where the front awing support was attached to the side.
Looking thru the frame, area is unfortunately directly over the front gray water tank and fresh water tank.
I contacted Thor and they were going to have be re-enforce the floor from underneath, but that would mean dropping both tanks.
I have found some other posts that over time this type of "built up floor" can fail due to glue failing.
I'm thinking of getting some laminate style floor (tongue & grove) and just laying it over top of the area. (after peeling up linoleum and verifying / fixing water leak)
I'd be curious about what you may find.
By the way has your front cap/covering come "delaminated"?