I have had that same issue, I used a little talc on the seal, but it was pretty temporary.
I was so pleased with the results I got from using 303 protectant on the roof of my RV, I used it on many other areas. It really takes the place of the 'Armor-All' type protectant, and it lasts longer and doesn't attract dirt as much. I also like that it doesn't make things so shiny and as slippery. I use it on anything vinyl, like the dashboard and door panels in my vehicles.
I will have to try it on the MaxxAir seal. I usually leave the vent open just a little for ventilation during storage, and I suppose that helps to keep the seal from sticking.
Doug and Patience and Shelby the mutt
2015 Crossroads Sunset Trail Reserve ST26RB
2013 Ford F-150 3.5 EcoBoost XLT Supercab 4x4