Yes, that is normal if........ you (or the previous owner if you bought the car pre-owned and dealer didn't check the spare tire bay) had a flat tire once and used the spare tire in the rain or wet condition then put it back in the spare tire bay without drying it.
This is what my buddy had on his Rogue as well. He bought it pre-owned and the dealer didn't even check the spare tire. Salesman said that that it just came in the day before and went straight to the lot. Turned out that the spare tire was changed to full size and was last usd during snow season. You know the rest.....
