Live cultists cannot be recovered.
Correction: the unconscious enemies are not recovered. Those, who surrender, are recovered correctly.
To reproduce, load the attached "stunning doesn't work.sav", go down-left and shoot the last enemy. If you finish him the same turn, you get no prisoners at all, if you finish him the next turn, you only get the ones, who recovered from stun and surrendered.
Update:
Experimented a little without mods in "New Battle". Stunned enemies seem to count as dead. Another engine bug.
Update 2: Experiments are invalid, because "New Battle" always kills prisoners. Meridian said it's an engine bug, but the one that only reproduces with The X-COM Files.
P.S. Can the mod version 0.8 work with an older version?
Note to self: reverting to the previous version:
git reset --hard 61d22e5f6b770249fd06a13db5ff276875c225a5