I bought a used 320 compact a few weeks ago that had a manufacture date of may 2015. Had multiple failures to extract with 124 grain speer lawman per magazine. Interestingly it had no problem with 115 grain blazer brass. Returned the pistol to scheels who has an awesome 30 day return policy and they sent it back to sig and I ended up buying a new may 2017 manufactured 320 compact. Haven't had any failures within the first 250 rounds but have experienced some erratic ejection with 115 grain blazer time will tell if that will change. Ejection with the 124 grain lawman is robust though so that's good since I have a lot of that ammo.
I have heard from a trooper buddy of mine in Oklahoma that they had to turn in their first issued 320's for new ones due to failures to extract.