Was going through the forum looking for this exact problem. Not sure if you figured it out yet, but I just fixed mine and it is very easy. What happens is the trigger bar post gets bent slightly forward which will not let the bar hit the sear. Put your trigger bar in a vise and use your hand to slightly bend the forward post back into place. I placed it in the vise with the long end facing to the right and gently pushed to straighten out. And also the bar itself becomes a little bent from the pulling motion.
I ordered a new bar after I had reworked my previous bar to the original specs. At least the nub that hits the sear which was worn. When I put it back together it wouldn't catch. Not until I received the new bar did I realize the problem. So now I have two.
Good luck hope it helps.