Toast, I think what you are calling dual engagement is just the nature of the beast. Virtually all my linerlocks/framelocks do this. Engage further when "Snapped" open Vs slow and easy.
mone do a bit also just not to this extent. The soft engagement may be the thickness of a ppiece of paper and seems as though it would disengage with little to effort. I have tried to make it fail but it hasn't yet. I womder if it will wear into a more normal, further back engagement after a bit more usage.