It's annoying as hell, especially when you are fighting at hills and try to shoot a vanu at night that you can barely see and loose because your ADS get's interrupted because you "fell" down an inch..
It's not a bug, it was intended. When you slide down a hill even a tiny bit, the game considers you to have entered a "fall state" and kicks you out of ADS, a lot of this had to do with wanting to keep Light Assaults from ADSing while airborne, but apparently they've now found a workaround, and getting kicked out of ADS while entering a "fall state" is being removed next patch, which should be in a few days. THANK GOD.
What he said. However it was announced that this would be reverted back to it's original state at some point. If it's here in April, or later in Summer, time will tell. I quote
