Update: talked with manufacturer (great guy and very responsive) and they indicated that most likely I would have to reupholster the area.
This is not the first time they have seen something like this (important to keep life jackets and other materials off the seats while covered).
My understanding is that Simtex is made by heating up a chemical compound. The heat inside the covered pontoon heated up the life jacket emblem (most likely some other plastic compound) that resulted in binding the two together.
Not much you can do to reverse the process given that we are not trying to clean the Simtex.
Note that Bennington uses custom Simtex colors, thus another reupholster complexity.
While my situation is not ideal, I was lucky in that the area is behind the co-captain chair and is less visible.
