Can you message me and we can get it replaced? This will generally be a consequence of overtightening. If you are mounting to a brace and not across a pane or trim, the best solution is to fit o rings in a groove on the one side and a rubber cap on the screws, this increases grip without the tension. This issue tends to be most common in the US and with so called "euro braces" which ironically almost don't exist in Europe. The main issue is that US tank builders bevel the edges (European builders just sand them) and a considerable amount of surface is lost to the bevel so customers tighten them to compensate and of course once it starts to slip, the bevel is a ramp right into the tank. We have been working on a solution but it is tricky, we have a plastic that won't break, but the second you overtighten it, it turns to a frosted opaque color from the internal tension in the plastic and looks terrible and the change is permanent they do not go back to clear when the tension is released. Adding some rubber generally seems to be the best fix with cautioning against make it too tight.
