After having some very in consistent results with Wisp Tea during the Astra Malorum boss fight I decided to do some perk testing first before trying another run.
tl;dw unless it was a bug, Wisp Tea (with Fox upgrade) does NOT revive you if you have no equivalent exchange charges left on your Quick Revive
The fact that this perk also snatches the 2nd perk slot, even if you decide to play without revival augments, is very unfortunate 🫩