It's been consistent since the odyssey launch. One entry on the list is always blank, and if it's the last one then you can't track them.I ran into that. Hopped into my SRV to check: was in the power building.
Last time I had trouble with it was when I set the power reg shutting down early to save time, figuring 3 minutes would be enough to clear the workers out of the IND building (I'd already had a fight with the guards) and it turned out that the very last person wasn't in there.
One mildly-distracting fight with a bunch of scavs later (they literally spawned in the courtyard before my eyes when the power shut off, didn't even have the courtesy of pretending they were dropped off by a dropship - I guess you can get away with that if you assume the player will be in the power building when the power gets killed) I had to recall my ship and use the SRV to find the guy - he was in the CMD building in one of the rooms I forgot to check, I'd cleared out the security section but forgot to cross the hall into the ops room.