Instead of dealing 5 instances of damage on a Tesseract heavy attack, it only does 1 instance of damage. With it only hitting once on a heavy attack, it essentially does barely more than a light attack while consuming triple the ammo cost. Temporal Sprint/Tesseract also is extremely inconsistent in refreshing itself on kills. I often couldn't ever get it to chain more than once. I'm pretty sure the reason the perk doesn't refresh is because it's the AoE attack that refreshes Temporal Sprint, so lunging directly into an enemy and killing them doesn't refresh it. With how it used to use half the guard energy for the first burst and the other half for the second burst, the first burst's guard cost carried over so at most you can only chain 4 heavy attacks in a row (and that's if it can get that many in a row in the first place). Doing a mid-air Tesseract also still uses full guard energy so it's impossible to do back-to-back heavy attacks. Even if you get a kill this way, Temporal Sprint will refresh itself but be unusable.