I'm not familiar with the barrels. My guess...
They have had a couple barrel changes. The first barrel had accuracy issues. The second barrel didn't fix it, and it was redesigned again. There was something wrong with the crown throwing off the bullet.
Sometimes there are changes made without the manufacturer drawing attention to something.
Yep. Look at the striker on the P365. It's been redesigned at least 3 times since it's introduction.