NickT said...
Those plastic brackets are crap, would be better off with four holes rather than a slot then they wouldn't slip or pull screws.
They are still the most comfortable straps ive used though.
They are begging for a better board to plate connection, lets hope this year the designers have given that are a bit more scrutiny?
In the meantime, any Cab dealer cab supply you with new plastic brackets for free, and if they can't send me a self addressed post pack and I'll send you a set of brackets.
I had this issue a couple of seasons ago but discovered it was someone in the shop re-adjusting my syncs in between each ride. They got given some special cinnamon donuts now I don't have the issue anymore!

Possibly your brackets are worn (the recessed steps for the screw head) allowing movement under landing loads. Best option is to replace, or grind 1 thread off the screws so they tighten down more.