1989TransAm

i recently had all my rubber weather stripping replaced where the t-tops are and where the back window is, in all possible spots. the problem is that everytime it rains, the cloth drops down a little, but when it doesn't rain its fine, and doesn't look like anythings wrong with it. i felt the cloth with my hand while it was dropping down, i didn't feel any moisture. is it possible that even though it doesn't leak, the cloth will still drop down, at least that's what my dad says, but it doesn't make any sense to me. btw, i have t-tops, and that weather stripping was replaced as well.