had you researched the topic a little more, you would have seen that certain BRANDS of brass have KNOWN primer pocket issues. THE S&B, for instance has smaller flash holes and a primer crimp; the ivi, winchester nt, and federal are all crimped in primers- moreoever, when you go to chamber this range brass, you will find that some will, some won't- UNLESS you use the lee factory crimp die- this is due to the difference in chambers between manufacturers; but back to the primer thing- i just run all of mine through the LYMAN primer pocket cleaner ( it's a hand tool) whether they need it or not as part of my case prep- lee presses do funny things when they run into a primer crimp , and i'd rather NOT deal with that- and are you sure you used the EXACT same pressure to seat EACH AND EVERY primer- your "symtoms" sound to me more like INCONSISTANT PRESSURE more than anything else- or there's media or crap in the primer pockets- either way, get out your bullet puller( either type- i like the hammer) and do it again- and don't believe the crap about unseating live primers, PRESSED out, they won't go off-
i also use a LEE hand primer tool, not the one on the press