If you have water getting past the black seals around the slides, that's different. They generally last for quite a few years. But sometimes they can tear or come loose, or water can get around them for various reasons. I think that type of problem would be covered under the 1 year warranty.
The seals/sealant discussed in the warranty statement is the white/clear caulking at the seams of the front and rear caps, the seams where the roof meets sidewalls, sealant around light fixtures and windows, around vents, down the edges of the caps, etc. The sealant can last for a few years, or not. It needs to be frequently inspected for cracking or separation from the surface being protected.
The real problem is determining where the water is getting in. From a warranty standpoint, if the dealer determines that the caulking has deteriorated, that's one thing. If it's water leaking because the black seals are not doing their job, that's another.