After playing for some time and being confused by this, I finally figured out that if you start the Volatile Rounds buff via Gyrfalcon's or Stylish Executioner, your VR will not pierce barriers or be anti champion, as noted by the icon on your weapon. However, VR initially granted by either the artifact mod "Volatile Flow" or the fragment "Echo of Instability" will give anti barrier capabilities. Extending these buffs will not grant or remove the anti barrier perk regardless of how you refresh it, as it is completely based on how the buff was initially gotten and will remain as anti barrier or not until the buff is expired and gotten in either way stated above. Would really like this to be fixed as it has started to really impact build choices. (credit for the paragraphs go to a reddit user, just posting here to up visibility to the bug)