Please help me out here. I'm playing The Lost Valley DLC, and my Ranger Marksman reached Lvl 7. The "Step Back" ability sounds great. I attempted to use it multiple times in combat, when my ranger is within melee range of an enemy. The "Step Back" button appears in the Bonus action section. But if I click on it to use it, the "Proceed" button does not work. Instead, it says "Execute your action even though it is incomplete", which makes no sense first of all, but even when clicking "Proceed" multiple times nothing happens. I can only "cancel". The ability appears broken.

Or, am I doing something wrong?

Thanks for any help!

UPDATE:

So the above test I was doing, was in a scripted cave area with giant spiders and trolls.

There is a possibility that the Step Back ability doesn't work as well when there are large+ enemies, or perhaps close quarters like that cave was (even though I could take a step back and suffer an attack of opportunity, the Step Back ability would not allow me to pick a square to move to when I'd attempt to use it), but works fine with medium/smaller enemies?

Because: I finished that cave and moved on to the world map, getting into a random encounter with medium sized orcs.

The Step Back Ability worked!

So, something is either buggy about that cave, the tight quarters, or the enemies themselves.

Anyway, I'm able to use my ability and move on, at least for now!