Slitherine

Whats wrong: My unit, Marna's Gendarmes, destroyed an enemy unit and it's rollup did not trigger. Tried multiple times, but no luck.
What I was doing: I was fighting Iron Barony and I charged an Archer unit that was at half health, taking it out with that one charge. However, My Marna's Gendarmes (which is an auxillary unit mind you) did not trigger it's rollup effect which was suppose to let me get a new attack action and 2 move points back. I did the same with a secondary Marna's Gendarmes with no luck. I kept trying and it never triggered, ergo - this effect is either bugged or not implemented. Not sure if this problem is with Marna's Gendarmes only.
Method of Reproduction: Deliver a mortal blow with Marna's Gendarmes on any unit.

I was looking at this script last night, I'm a little fuzzy because I look at like twenty of them. I think I remember some exceptions that negate the ability. Several where terrain related, off hand I can remember it didn't work in wastelands or forests(unless Elven), and water seem to negate alot of abilities. I think there was an exception if the unit was an auxillary from another country as well.

I'm fuzzy on if the terrain limits are based on the province's terrain, or the hex of a tactical combat.

This is a known issue, roll up does not currently work.

Regarding terrain effects - in auto battles it will use the province terrain if it needs a terrain for anything, in tactical battle it will use the current hex.