How to loop around [action_user]?

Hi Kyle,
I have a CODE type push notification (I have simply copied your system action for Comment Chain notifications) and then added my own code (it sends out push notifications to the phone associated with a certain UserID).
The problem is that AA loop around [action_user] fine when set to Activity type, but do not loop around [action_user] if they are set to CODE type.

How can I achieve it that it loops?

[action_user] is just the user id that originally fired the auto action. It is not meant to be looped. You can access the looped user with loop_ substitutions. So for example if you need the user id you can use [loop_user_id]. This is noted in the description of the Parameters > Loop parameter. If you mean you're just acting on an array result from User then you wouldn't use [action_user] at all and would just use [user_id].