I assume you mean the first round fired from a freshly loaded magazine which has been inserted into the XCR and not the very first round of the day fired from a cleaned barrel. I had the same thing happening in one of my AR uppers in .223. I tried differing approaches: letting the bolt go forward with the bolt release; letting the bolt go forward by pulling back the charging handle and then letting go; not letting the gun run dry by leaving a round in the chamber and inserting another loaded magazine. In the first 2 choices it wasn't chambering the round with the same force as having fired the rifle so the bolt wasn't locking up exactly the same. The more I fired it, the less the first round would be off; finally the first round stayed in the rest of the group. I figured the bolt lugs finally wore in with the barrel extension and made the whole area smooth enough that the bolt always locked up the same, regardless of force.
Advice: keep on shooting and see if the situation improves.