Both of my trapdoors have a good bit of trigger creep and I suspect it is not uncommon in the marque.
I solved the problem in the one I am building by layering heat shrink tubing onto the sear.
This got creep down to about a sixteenth inch where the finger bears.
This is a three position tumbler and I want the trigger to be right. If the tubing lasts, I will do the same thing on my other one.