I haven't had any of my Talon grips peel on any of my guns but I im a little excessive on the cleaning . I'll hit it with the supplied alcohol patch and then take a tooth brush and a rag and a bottle of alcohol and clean it again . But I see what you mean about the corners on the Shield although mine haven't been on that long they seem to being staying put and I'm wearing my shield IWB .I used to have the rubber talons on my shield but the corners peeled up on me. It could have been a mistake I made during installation, but I went by the book and took my time. Anyway, I'm needing some more grip on my shield and I may give them another go. Undecided between the rubber and granulate this time though.
Another thing I do is after I put them on is I'll watch TV and sit there and press on all the edges/corners for a while . If I were you though and the rubber gave me trouble try the granulate maybe you'll have better luck and maybe try doing what I did for the application .