The Mariner is made of a non-stretch material (they don't seem to say what it is, but looks like nylon). I used to use a different seals (coastal tour, IO think) that was nylon, and it would pop off on rolls. The fact that it doesn't stretch means it will get pulled a lot during the body motion required for a roll. A neoprene skirt may do better, as the stretchy material allows for motion more.
There also may be slight issue of skirt size versus combing size. All sprayskirt manufacturers make skirts in set sizes, and these don't always match the cockpit combing sizes. Not saying I have heard of this being an issue with Tempest and seals, but it is possible.