I appreciate this, you are the only person who acknowledges me posting this error. I can make this change with the information you provided, but I am reporting this error so that Trinity will have this functionality restored to how it was in version 2.1.4.
A little back story; a month ago, there was a version of Trinity called Unified Trinity. A user named Jubisman took all of the popular modifications to Trinity and released the edited version for us to download. The Shotgun Crusader worked by default with Unified Trinity.
Unified Trinity was merged with regular Trinity for v2.1. The shotgun crusader worked properly by default with Trinity v2.1 all the way through v2.1.4. Starting with v2.1.5, shotgun crusader stopped using Heavens Fury on single trash mobs. It still works perfectly on single elites and 2 or more trash mobs.
I am hoping that this can be corrected since it previously worked fine. If this were something that had never been implemented, then I would request for the feature to be added. As far as I can tell, this is a bug and not a lack of features.