I am currently trying out a stamina build with a Two-Handed weapon, but am finding that quite often when I follow up the Uppercut skill with a heavy attack, the heavy attack does not connect.
I don't have any issues with lag as far as I am aware, and I have the enemy properly in my sights so that they have a red halo and their health bar is showing.
It is getting a bit annoying as I have Uppercut morphed to Wrecking Blows, so the first hit after performing the skill is more important than most.