Direction multipliers aren't passed on to the prediction GUI
Works for me. When you are in the prediction window, is the activeEvent facing the targetEvent? If not then that's the problem. I recall encountering a bug where activeEvent only faces targetEvent after an action is confirmed (so directionMod works but only after an action is confirmed).
Make sure directionMod is near the bottom of your plugin list
When the prediction window is up, use the following commands on the console:
$gameTemp.directionEffect()
and
$gameSystem.EventToUnit($gameTemp.activeEvent().eventId())[1].action(0).itemHit($gameSystem.EventToUnit($gameTemp.targetEvent().eventId())[1]);
directionEffect shows the direction of the attack (front/side/back)
itemHit will show the true hit rate of the action.
Direction multipliers aren't passed on to damage formulas
directionMod does not change eva or hit. it changes itemHit and itemEva. If you want to use it in a damage formula, use itemHit(target) and itemEva(target). Both functions are clunky to use in damage formula as you have to define the target and it is a property of an action (vs a property of a battler). I would use $gameTemp.directionEffect() if you want to modify the damage formula based on direction.