Does the bolt catch move freely when hand worked up and down with the upper open.

If so, then could just be the anodizing/parkerizing surfaces just haven't mated in yet.

Lock the bolt back on the catch, pull the CH all the way back and let the CH fly forward, the bolt catch should drop out of the way and allow the bolt charge home.  

Another check is to just lock the bolt back on the catch, then bang the butt stock on the ground hard.  The bolt should charge forward as well with the catch dropping out of the way (no mags inserted into the rifle on either test).

If the rifle passes both tests, then it's new/rough parts that need to self polish through use/live fire.