Did recent patches changed something related to NPCs and killmoves?

I had a mod which let player and NPCs perform killmoves based on the attacker's skill with the weapon he is using (the higher the skill the higher the chance to score a killmove - if the target is not blocking).
At that time the game version was 1.6.89 and it worked perfectly.

After my game got updated to 1.7.7.0, i had to create my mod again from scratch (in case something has changed in the anims), but no mater what i do, the NPCs never use the killmoves.
I even removed all the conditions in the animations tree, resulting in player using killmoves all the time, but the NPCs are not using them at all, never.

Is there some kind of new global variable/setting, controling whether the NPCs will use killmoves or not?
Why is it not working?

Maybe it will be better if i provide an example, so here is how i created my "test" mod:

1.) Start Creation Kit and check "Skyrim.esm" and "Update.esm" in File/Data dialog.

2.) Find global variable KillMoveRandom and change its value to 0.

3.) Open Gameplay / Animations window and...
...under "ActionRightAttack" in Character animations tree, find "KillMoveShortB00" and move it to make it the first child of "KillMoveFrontSideRoot00".
Remove ALL conditions from "KillMoveFrontSideRoot00", and make sure "KillMoveShortB00" also dont have any conditions (shouldn't, but make sure).

4.) Save it as a "test.esm"

5.) Run game launcher and in "data files" make sure the "test.esp" is the only ticked item, and launch the game.

6.) Load some save, write "player.placeatme 46794" into the console to spawn Imperial Soldier near you, and go swing at him.

Observe:
Player is using the killmove all the time, but NPC is fighting normaly like if we didnt change anything.

Why? and how do i force NPCs to use killmoves whenever i want (ie. when given set of conditions in the animation tree is met) ?

After recreating the addon again from scratch, the issue disappeared.
But i still think something is different, because in the older version the killmoves were kicking in more often.
And i'd still like an explanation why the NPCs are ignoring the changes i described in previous post, but... i guess i'll never find out.