This does not necessarily mean that there was a problem with this particular ammunition as there are other causes that could result in the primer missing. It could simply be that the primer pocket was reamed to large when the stakes were removed from the NATO brass or that if reformed by using a primer pocket swagger there was debris left in the pocket that resulted in the over-sized primer pocket during the swagging process.
If this was re-loaded ammunition, then the load data has to be looked at very closely to try to determine what happened. It is usually impossible to double charge a rifle round and most pistol rounds due to the standard charge weights filling more than 50% of the case. If you double charge, the excess powder will fall out of the case and you have powder all over the place. However there is still room for an over charge in these cases.
I have seen a number of cases where the primer was blown out of the case on non reloaded ammunition as well as reloaded ammunition simply because the primer pocket was reamed to large for the primer. On multiple reloaded cases, it is usually one of the indicators that the case has surpassed its life expectancy and should be culled from the remainder of the cases.
All this is speculation though until we get the information on the ammunition used.
And yes, LC does mean Lake City. It is a NATO standard brass that has thicker walls than normal brass and when reloading it you have to cut the powder charge down by 5% or more due to the decreased volume of the case.
To the OP: You might want to check to see if the extractor on the bolt is OK as well.