Looking at a new trigger, the area where the sear rest on your trigger looks like it's has a slight angle. My new trigger appears to be more of a 90deg angle. The nut is what's adjusted to allow how much of the sear you want riding on the lever.

I would hate tell you to take a file to the lever, but if you do, be super carefull and do a little at a time. Don't file the sear.

I have installed many with no issues and I don't remember any that had this much angle. The sematic picture shows the angle @ 90 degs.

Rifle Basix is good, give them a call and maybe email the pictures. Get the answer from them directly.

Dennis