Ara-Kara - issue with grasping blood on last boss

Hey!

I'm currently playing an alt (Pal tank) and something quite awkward happened to me, twice already.

Grasping blood just disappears without any kick or stun, releasing me during Singularity channel. It killed me once, I managed to survive the second time. However, that's quite annoying and I'd like to figure this out before returning to the dungeon.

I don't do any intentional damage on grasping blood, I just wait for the cast to end. Did any of you have the same issue? Or any idea on why it happens? Maybe it's because of passive damage I'm not aware of, something like that?

If you have any tips for pal prot on this fight, I'm all ears!