Leedsichthys Undertow attack not registering serverside/not actually attacking or landing

I noticed during fights that there were several moments where undertow would not pull enemies towards me despite them being with range. I was under the assumption that this was possibly causing undertow to not do damage so I recorded this happening with a friend on official servers down below. What would happen is there would be times that I would press the Undertow attack button and the animation would go off for me and the cooldown timer would begin but from my friend's point of view, they would not see the animation for undertow go off and it would not hit them. We tested this several times and it seems to be consistantly happening ever few undertow attacks.

The animation for Undertow would appear for me and the cooldown timer would begin for the ability but it would not hit other players and they would not see the animation for undertow go off.

Undertow is supposed to hit them if they are in range and they are supposed to see the animation for the ability when it is used.