Basically, I've noticed on multiple occasions, even for instance a Grineer tileset; where I'll just have Grave Spirit (Base) active, which should save me if I am downed, instead I just go down and and deactivates. I have not been able to replicate this at will, but it happened multiple times in this mission, yet other times it saves me.
Hiho!
At 2:23 in your video, you walk through a Nullifier bubble (enemy located behind you) which turns off the ability.
Does it only happen during mission with Corupted/Corpus enemies?
Cheers!