I just experienced the same thing with an Edge 308. My reloading manual showed the catridge used was 2.78 for 178gr Hornady A Max but after shoving my bullet in the brass with the bolt it seated at 2.890 I set it down 3 thousandths more to 2.887 It wasn't touching the lands. I gave it 10 thousandths more and my COAL is 2.877 vs what the book had at 2.78, BIG difference.
From what I understand the minimum OAL is the measurement that is important. NEVER go under that. If it is over it's no big deal as long as the bullet is seated good in the brass and it will feed from your clip.