I JUST noticed this during a Crashsite match on Sanctuary. I was holding down on my RT and nothing happened. I couldn't melee, throw a grenade, or ADS. After I died (obviously, since I couldn't defend myself in any way ) I was then able to fire my gun. Has anyone noticed this happen?

I guess it's the lag. In some games where I have only one red bar I find that sometimes when I try to fire a hologram it takes up to a couple of seconds before I can deploy it. When I press the RT too soon after pressing left on the D-pad, I just fire bullets or nothing at all.