I'd like to suggest that either they don't, or that if they do they stay gone... 
I know it's meant to make NPC's seem more realistic and care about their survival, and in most cases up until recently if they did wake out then immediately respawn and have another bash they generally stayed till the end the second time.
I just had one NPC wake out and respawn five times. There were another three incoming enemies that never got a chance due to this ones rather futile persistence.
So, for mission spawned NPC pirates that interdict players, can they either fight to the end, or take having to wake out as defeat in the same way that they seem to take failing an interdiction a defeat.
I know it's meant to make NPC's seem more realistic and care about their survival, and in most cases up until recently if they did wake out then immediately respawn and have another bash they generally stayed till the end the second time.
I just had one NPC wake out and respawn five times. There were another three incoming enemies that never got a chance due to this ones rather futile persistence.
So, for mission spawned NPC pirates that interdict players, can they either fight to the end, or take having to wake out as defeat in the same way that they seem to take failing an interdiction a defeat.