It's typical.
As Audrey and Rich said, the depreciation slope on a motor home is very steep the first few years. The Excel screen shot I attached below is an average of what happens to the value over a 20 year period.
I have no idea how lenders policies may have changed recently, but the guy I purchased ours from left his paperwork in the glove compartment
. He had a 15 year note, and based on his monthly payment it was a straight line amortization loan. The MH was six years old at the time I bought it and paid 50% of his original purchase price.
Yep, he was definitely underwater.