I can only assume that you have a Winnebago Journey, that only has a 12 month warranty for the item in mention, unless you have documentation indicating that you've had problems with that seal before. If not, that job "can be" labor intensive and they charge an arm & a leg for the seal.
I don't know if there is a story behind it, but it's not an uncommon problem and it's not wide spread either. It's just one of the items that can cause more stress, when it's not necessary.
Tomcat F15