It looks like your roof is constructed the same as mine. There is an strip of aluminum rounded over the edge and fastened with either staples or small screws. That is probably what you are feeling when you press down on the rubber. As long as it doesn't pull out from the molding holding it down on the side I would leave it as is - that is if you think it has not leaked.
If you supect it has leaked or just want to get it back down, I would do as already posted and make a slit in the rubber, fix the situation under the rubber, and then glue it back down and cover with a 4" wide strip of Eternabond tape. I used that tape on my RV over 14 years ago and it still is holding today. Great stuff! :)
Here is where I purchased mine. They had the best price that I could find.
Barney
