Not sure if this helps but I found on my older AccuTrigger that if I adjusted it too low the same thing happened. Also, once I got it adjusted correctly, the adjustment spring would loosen by itself during use and the problem came back. I finally put some nail polish on the adjustment...
I had the same problem with my Savage (2011 model). I would adjust the trigger pull weight at the lower end and as I shot it, the trigger would get lighter on its own until it eventually would do what is happening to you. The screw was backing itself out. About 8 or 9 years ago I put nail polish...
Just curious, which Break Kleen did you use? I tried the newer "Green labeled" version and it left a white crystal like material behind on my parts. I went back to the original "Red Labeled" version.
I have seen shooters create targets that are set up with specific MOA or Mils spacing to test their scopes without shooting (similar to a tall target test target). Plumb the target at 100 yards and then mount your rifle in some way (lead sled, etc) to hold it in a level (plumb) position. Align...