It seems quite odd that furniture in a 3 year old RV should suddenly start to disintegrate. Especially since it is more than one piece that is involved. It definitely is not normal. Is it possible that the furniture was cleaned with a chemical or some other product that could have caused this? Or was the RV exposed to an environment (dust storm, weather related, storage, animals, etc.) where the windows were open or somehow something came in contact with the furniture? Usually furniture falling apart is due to abuse or just plain poor quality of material or labor or both. Normal wear and tear will occur over time, not from returning from your most recent trip. You sound like experienced travelers so I would be inclined to think something happened quite recently. Good luck in your investigation and do let us know if you find out anything.
2016 Precept 35S