Eliminate Prisoners: I must be doing it wrong

So I picked up a couple of “Eliminate Prisoners” missions. They seem pretty similar to “Eliminate Pirates” but I don’t think they’re working right; or at least I’m messing it up somehow. I go to the system, I scan the NavBeacon, I find the area, I fly there, I scan ship in supercruise until I identify a “Mission Target”, I interdict them, and then I return their matter to the universe. They explode. Their materials float in a goodie cloud. A notification flashes that I have earned the bounty for my bellicose deed. And floating in the midst of the debris that once was their vessel is a wake signature, and a number is not ticked from my mission tally. They’re dead. I watched them explode. It told me that they were killed and their bounty was mine. They were a mission target, and they are no more. My collector limpets took everything useful that once was their ship. This has happened seven consecutive times. I have no other current missions. These are the targets that I’m meant to kill; not just merely “wanted” ships. The game calls them “mission targets”. What in the nine hells am I doing wrong? Have I killed my target at the exact moment of them high-waking away and leaving them in some ethereal superposition of fugitive and deceased? Seven times? In a row? wtf?