The Personal Void Shield for those who don't know or don't use it much creates a 1800 second buff that adds 500 Shields to your health, which regenerates during the entire span. The cooldown is a bit long but easily allows you to stack, limited only by the buff time (Which is huge) and the charges you can get. (4 to start out with, various abilities give you more of course).
However the bug occurs when dealing with cutscenes. If story log appears or you have a cutscene with a character, whatever form it may take, you'll find yourself with all of these buffs on you simply gone.
My theory is of why this is happening might be due to some spaghetti coding. On the Personal Void Shield is mentions that on death you lose the buff.
So during a cut scene it move remove your character from the session. I'm pretty sure it does this so you don't die or get attacked when you shouldn't. That's all fine and dandy but the game either counts you as 'dying' or 'returning' or whatever trigger to remove the charges rather then remembering to keep them.
Hopefully this can be fixed soon because it's quite a useful thing.