Ok the 0 base was confusing. The only ways it seems to be not working as intended is that it won't engage during an enemies recovery, which I think is on the known bug list, and dual wielding spears with the modal still only results in 1 engage.
I've never seen a second engagement connection while this modal is active. I don't think it's increasing the count like it says. Ah well, I've only forsworn every other weapon in the game at character creation.