I was fighting this Vex Minotaur and something went wrong when it initiated it's teleport.

Kalamari and I witnessed this yesterday while patrolling Venus near the Ishtar Cliffs, although I think it was a harpy or goblin that went invisible and kept shooting at us.

I ran across a Goblin in that state once. I didn't see how it got that way, but the teleport seems like a possibility.

Vex are supposed to be able to warp space and TIME. Maybe he's shooting through a portal to another dimension or something?

the second DBO raid run, we ultimately had to go back to orbit and retry, because one of the Vex did this near a capture point, and it was nigh impossible to cap it, since we were under constant fire and couldn't hit him back.