I can't see your cases from here so I can't be positive but I suspect your "bright ring" is normal burnishing at the point they begin to permanetly expand and resizing stops; don't worry about it.
As a side issue about your dies, I've actually measured the work from a good number of our various die brands. They ALL let an occasional clunker out but they ALL replace defective ones. I found that, on average, Lee's dies are as good - or better - than any other common brand (and their collet neck dies are about as good as neck dies get, at any price.) Anyone wishing to argue that needs to bring along some hard data from actual measurments from a statistically valid number of dies, not just one set or based on "I know a guy who's cousin's neighbor once said his daddy told him...", etc. Fact is, ALL dies are inside reamed to SAAMI specs, no more, no less. And it's the insides that do the work, shiney exteriors and neat knurling are pretty but they are only eye candy.
In my tests, ONLY Forster BR dies, and Redding's Competion copies, were consistantly a bit "better" (more concentric) in the ammo they produced.
The RCBS (Ohaus made) 1010 scale is THE "par excellance" reloading scale. Mine is as dead on accurate and sensitive now as it was the day I took it out of the box (as a Lyman M-5) in '65. And I fully expect it to be so in the future.