I have noticed the exact same thing happening with my crotch strap. The continuous thrust pulls the Triglide towards the crotch strap, and then the buckle cannot be removed without adjusting the tri glide. I may have to do some sewing to keep it in place.
Exactly the issue I've had.
25 bucks (what they were at the time) to CA to solve that problem for me was well worth it, to me.