The 4th skill on Bolt Pistol & Chainsword for the Sororitas class ends prematurely and sometimes randomly before running out of ammo. I have tested with keyboard and assigning it to multiple buttons on my controller to make sure it isn't a faulty key.  Bumping into any terrain, enemies, walls will sometimes end the channeled skill before I let go of the button.  This can be replicated VERY consistently by moving into corners, or over certain raised terrain.  This is quite frustrating since the ability has a significant cooldown.   The spinning move on the greatsword does not seem to suffer from the same problem, though I have spent much less time using that.