Tbh I havent checked it mechanically in a while and I'm probs not going to play until the live aoe testing happens, but depending on how they made the gap closer function work it could be snaring/rooting you through immunity while the blastbones is mid air. Gap closers were made to do this way back in the day when zos tried to mess with them and could never make them work properly. Currently most gap closers were reverted to not do this absurd no counterplay mechanic, some do exist like dragon leap and I think the dw gap closer still does.

---

I wouldn't be surprised if it is this, pretty much anything that checks positioning between two points has issues. Especially streak, which has been butchered since its initial stages. Conal abilities like breath of life can root you in place temporarily if you are turning your mouse while it is cast, this is so it can figure out positioning and placement. Ground placed abilities can do this aswell like blessing of protection. Caltrops used to do this alot aswell, but zos did some work on the ground casts that actually helped a little.