It happened to me once in storage. A Bailey Arizona. They got into the gas cupboard, I think by climbing up a steady then along a wire to the gas drop. But then they found their way up the cavity between the front two skins. Then they made a hole just above the shelf over the front window. They did some damage to the tops of curtains and found their way down into the front locker and built a nest.
I was able to fully clean and tidy up and make minor repairs. Tried my insurance but they do have a rodent clause so no chance there.
But your suggestion about warranty might be (I don’t know), possible if it can be shown that poor design or construction allowed the entry.
They can be stopped by blocking their little holes up with polyfilla. But first you need to catch them!!!
John