We're fixing a couple more instances of the Reviver not working properly with Title Update 3. Feel free to test it on the PTS right now and let us know if you find more instances of it not working.
Reviving, it turns out, is pretty difficult to get bug free due to some circumstances of how you die, with which effects on you and what you're doing while you die. We'll get there eventually, but I can tell you the devs put some serious work into fixing the bugs we found so far and it's unfortunately not easy and every bug needs its own fix.