Seems to be alot of trouble with the 4" memory foam toppers???
We just have the 4 inch seat cushions with the $59 Wal*Mart 1 1/2 topper and it works great.
Before we got that I insisted we put flannel sheets over the cushions and the wife did not see any wisdom in this as we were sleeping in sleeping bag
but this helped hold the cushions together.
I think like any product you will get a reject once in a while but if the 4" stuff doesn't work try something else and at the cost some of you spend, I would for sure get my money back.
Gerry the canoebuilder