Powertread Hunting Shoes Not Applying Bonus Correctly?

https://imgur.com/a/jN26GtS

The pair I have reads +15 to Crit damage per power charge. Please correct me if I’m wrong, but that’s an increase to the base Crit damage bonus. Because it’s an increase to the base, the increase % Crit damage from skill tree should scale to the added base. But in every scenario I’ve tested, the increase % crit damage does not affect the added crit dame from the boots. Is this intended? And is any else experiencing the same with this unique?