Well I also have the 18V24D. I bought it new and it had no protective cover - no cover at all. It is just the awning fabric. That's very interesting. The fabric does indeed stick to itself, vinyl. On my rig it is where the A/C condensate runs off and collects dirt etc. onto the vinyl. I've learned to extend the awning and wash that spot when we wash the rig. If it is clean it does not stick. Otherwise on the road you must pull the arm out while extending and then all is good.
I just watched several videos of the '18V24D, including at Lichtsinn. There is no cover on any of those either, just a naked awning roll.
I haven't sprayed 303 on it yet, good idea though.