They are probably quite rare. I haven't seen any in the Hydran, Gorn, or Romulan yards when I was playing them.
Indy, on that mission, did you check the news afterward? If there's no report of a battle there, then it was recorded as a draw somehow. Were there any pirates in the mission? I've found neutral non-cartel Orions seem to mess things up, but I don't have enough data to prove it.
Speaking of which, there are way too many non-cartel Orions showing up in scripts. They really don't add anything, and tend to complicate the results. Is there a way to cut them out of the scripts, or severely reduce their chance to spawn? The good news is so far the only cartel Orions I've seen have been in Surprise Reversed. Without any AI cartel ships on the map, they tend not to appear in the missions.
I was able to boost a cartel-neutral Romulan hex (captured from Fed) with a Fleet Action. The next mission had no DV change, but was reported in news, so I think it would have boosted, but the hex must have been at full health. That one was the Met_NW17Patrol. More info is needed.
Castrin may be swapping in a new testing map I threw together that uses more neutral space and mostly cartel-neutral space. All the DVs are equal to economy, so it will be easy to tell when a hex is full health or not.