The intended mechanic is to knock an enemy down and have the buff appear floating next to them for you to pick up. For some enemy types, namely, but not exclusively: MOAs and Ospreys, the buff will instead be launched into "outer orbit", making it impossible to collect the buff you are supposed to extract from the enemy, forcing you to pick a different enemy type(like crewmen), where the ability would function properly. This has been in the game for quite some time now.