Love the royal shield, other than the bulwark of azzi my favourite looking shield.
Anyway, mklovin has a point but he greatly over exaggerates. The whole location is about 100 yards circumference, being 40 yards away from something that has an approx 10-12 yard hitbox running straight through the middle of the room is practically impossible.
In any case, next time you do it if you can - use a video capture software and show us, alternatively get as far as you can away and bind your screenshot key to something close to your hand so that you can take a screenshot of where you are and show us.
Tell a GM of the issue and ask for their advice, perhaps they will stress test it some more, or re create the scenario for you to show them or something.
In any case, I have only ever seen him enrage from hitting nothing, never seen him actually hit people when they are not within his hitbox.