im trying to figure out if its a barrel link issue, or something else.
try to make it hang up, with no magazine, by allowing the slide to go forward SLOWLY, MUZZLE DOWN, then, while it is hung, see if pushing on the end of the barrel makes it snap into battery.,,,,,,if this is the case,
if so, it most likely needs to be broken in.
many times bushingless 1911s are custom biulds, and very tight, such as the pro carry, and will do this when new.
usually the test where you try it pointed down vs pointed up will reveal the culprit.
the reason for this is that when pointed down, gravity holds the barrel at the end of the link, vs pointed up where gravity holds the barrel in the feed position, rearward.
im not a 1911 smith, but i lhave oads of experience with bushingless 1911s.
i think breaking it in will emiminate this prob though, as i suspect its just very tight barrel link/locking lug fit, since you say the round is already being chambered when it occurs.