I am not familiar with the CY 4000 but I think I might know what you are talking about. Maybe.
A friend of mine with a Bighorn had what I think might be what you are seeing.
When the slide was out, it actually went out a little too far, which allowed the slide floor to fall off the edge of the rollers that are attached to the coach floor. The result of this was a bow in the slide floor at the area that the slide roller was attached.
A slide adjustment took care of it.
Hope this helps in your situation.
Peace
Dave