Tooltip cooldowns incorrect on shift

While trying to get shift cooldown faster to make it my main skill I finally got it down to under 2 seconds… or so the tooltip says. Swapping out items multiple times and I have gotten the tooltip to go from 1.6 to 2.0 with items, but timing it out and the actual shift time is 3.6 or more, this might not seem like a lot since its only 1.6 seconds but as trying to use it as a main skill and expecting to be usable the skills actual reuse speed is double or more.