We were Imagine-rs, before Imagine's were cool!

On my birthday In Dcember 2016 we were 'just looking' (lol) to trade in our Jayco Jay Flight, when we happened upon a brand new Imagine 2600 RB.  Voila - this is what we have been looking for (in order of importance) : large rear bath with room for two vanities, walk around queen bed, high arched ceiling, recliners, lots of storage, modern flare.  No other competitor could win over the floor plan.  We have had just a few little issues, many of which were solved at our walk through, and the National Grand Design Rally.  However, we have noticed over 4 years that our main living floor is spongy, for lack of a better word.  Should we be worried?  Anyone have any experience with this?