pathfinder

Hmm, maybe we have different views of what that means. To me, an action itself is triggered the moment you declare that's your action. Then its effects play out. Taking an action is an instantaneous thing, but the effects of the action obviously are not.

I think this becomes a lot clearer if we look at a different action, Stride. It says "you move up to your Speed." But this obviously does not instantaneously cause you to move your speed. And yet it's fairly unambiguous that if you take the Stride action, that procs any actions which may trigger on an action with the Move trait immediately, before you get to actually move. I view Stand the same. When you declare you are going to Stand, anything that would trigger on a Stand (or on a Move action) happens. Then you physically get to stand up (unless one of those actions says you don't). Or, in the flavour, those actions occur partway through your attempts to stand up, and interrupt it.