When trying out Gaige, the Mechromancer class, I was trying out the Anarchy skill, which adds an "Anarchy" stack every time you kill or reload after emptying your magazine. It's supposed to lose stacks when you reload a non-empty mag or while you're in Fight for your Life.
However, I found I constantly just lost stacks for no reason. Even after mapping my Reload key so I couldn't press it and not dying, I would randomly find myself with zero stacks. A friend playing in the same game with the skill noticed the same problem, but he was able to gather many many stacks, mine rarely went above 10 before being randomly lost.
Is there some unstated reason you can lose Anarchy stacks? Is this a bug or is there some logic to how I'm losing stacks?