Your photos show the major components as being your originals, I'll guess that the small parts they replaced include springs, so maybe the extractor spring was replaced. That could increase the tension on the round as it slides up the breech face during feeding.
Also, the indent on your AE FMJ is a "smiley" which results from recoil force slamming the barrel ramp edge into the top round in the magazine. Some people have done a "rampectomy" by trimming that edge so this doesn't happen, other people leave it alone if it doesn't affect function.
Since your slide, barrel, serialized frame insert are likely all original, the only thing else I can think of is the takedown/barrel pin was replaced, and it may have slightly different dimensions than your original, which might affect barrel travel during recoil?