I suspect that it is a desync problem which makes the swordie’s char invisible on your end.
I imagine that on his and server side’s end, at the start he is hitting the anchor on the left. At 00:04 he moved to the other Anchor above and starts attacking it. Notice how the low health aggro’ed Anchor is following the expected path his character would have made if it was not invisible on your end, this is what makes me think that it is a desync issue… The part where the character slides into position also strengthen my belief (which I have seen sometimes when dungeoning in that same map and a party member is invisible to me probably due to desync) 
P.S. jumping over the guardrails and fences usually cause desync issues in this map (Another character looks like its just running straight into the fence and didn’t jump on your end, while he actually jumped and is someplace else)
Edit: inconsistent use of word “dungeon” and “map”, fixed.