No, this is definitely not normal, but we might need a bit more information to nail down what's going on here. Does the bolt come back (even if only partially), and leave a fired case in the chamber? Does it not come back AT ALL? Have you stripped the rifle down completely to make sure that the gas port is clear, and that the gas piston is seating properly in the forward position? Is the chamber burred or somehow other scarred in a way that might make a case stick in the chamber momentarily? Does the stock have the inner shield in place that's supposed to stop the op rod/gas piston from interfering with the stock or vice-versa? These are the sorts of things you're going to have to eliminate one at a time to figure out what's actually going on.