I had to do this on my Sunline fifth wheel too, since it had sat at the dealer with the slides extended for a few years all the tape had become brittle and was peeling back and or cracking where the screw heads were.
Once I had peeled back the tape I was surprised to find water beneath the tape.
Eternabond is the only proper fix here IMO as the OEM type of material will only last a few years if you are lucky. Sadly, most ever new rig I have seen including my 2011 are built this way and I'll be keeping an eye on it for sure. With four slideouts to worry deal with, it's going to be a time consuming effort to redo all these once they start to fail, especially since I will have to remove all four slide toppers before beginning work.
Jeff, Laurie, + kids
Three time former Sunline owner
2011 Big Horn 3670RL Fifth Wheel
2012 Chevrolet Silverado 3500HD D/A DRW, Classy Chassis Conversion, aka "Garage Queen II"
Hensley Trailersaver BD3 Air Hitch