Mr Pinky,
"Diamond Shield" and the similar product by 3M, can both be a serious pain in the a$$. There are many, many reports of all kinds of issues with both. I'm not a chemist so, I cannot tell you just what causes your issues and or, any other issues with that protective cover. I hear it's the sun, moisture, improper prep when installing it, extreme cold, maybe altogether, who knows?
Apparently we're pretty lucky. Our coach, an '04 Itasca Horizon, 36GD with the C-7 330HP and full body paint, has either the 3M product or, the Diamond Shield and, to date, it's flawless. Now, as I understand it, we're the 4th owners of this coach and, we purchased it right at 4 years ago with 40k on the clock. It now has close to 62K on it.
And, as far as we've been lead to believe, all the coaches previous owners, kept it under a drive under cover, as do we. In fact, it's got it's own RV garage, right next to and, connected to the house.
So, I'm fairly positive that keeping it out of the suns reach, whenever it's not being used, is rather large help in preventing issues of any type with it. But, even though "I" think keeping it inside helps, there's other folks out there that also keep theirs inside and still develop problems with it.
So, what's the best answer here, who in the world knows? Many have had those covers removed and, if paint damage resulted while removing it, had the front of the coaches repainted. And, many have not and will not, re-install the 3M or Diamond Shield.
I think it's a fair product and, does some good in protection of the front of these rolling Kleenex boxes but, to what cost? If one was to figure out how many coaches have had the coating(s) applied ever since the inception of them, then, figure out how many have had issues, I wonder what the ratio would be????
Scott