Flame rush doesn’t get increased cooldown recovery speed from Blazing flux node. Other sources are still applied (such as affix on boots for example).
Edit: Decided to just add it here instead of new topic. Flame rush has other, quite annoying, issue. Sometimes character casts flame rush in place even if there is no obstacles around (and it’s much worse if there is some stuff around, like stones/columns/etc), while flame rush animation is drawn as if character actually moved forward. Few times (literally just 2-3 times in 2 days) flame rush somehow managed to move me through cliffs on some maps, causing lags and moving me back at starting position after few seconds.