Malachai Desyncing?

So, I saw this playing lockstep mode:

Malachai did his teleport blast explosion, I moved south to avoid it, the moment is blast animation ends he appears in front of me -to my left to be more precise- casting tentacle attack.

He did so without any interruption, without moving or teleporting. When I mentioned it in guild chat they said its bugged. I think this should be a priority bug fix.
I have nothing against this boss difficulty, but this bug could lead to a lot of unfair deaths.

And if you wondering...

...yes I survived (thank god for quicksilvers), I'd like to thank Fleshrocket for killing Malachai for me, pretty cool guy. I might have died to that bug if not for his help.