NPCs sometimes don't seem to take damage on attack

[Hagbard]

Greetings!

Both me and Lans have noticed that sometimes an attack hits, but NPCs don't seem to take damage.
When this happens, there is no visible sign of Parry, Dodge or anything like that ( not even a 0 damage).

This video captures the instance
https://www.youtube.com/watch?v=882A84Us-EA

[Sic]

It appears this was after the use of a special weapon move. Does it occur at other times?

[Hagbard]

Yeah I've seen it happen when not using special moves as well.
Sometimes an npc like "a zealot" will take no damage for like 30 seconds

[Sic]

Primarily mages?

[Kristijonas]

I saw this on I think warranty officer?

[Hagbard]

I'm not sure its primarily mages,
the Eldra illin for example is not a mage.

[silvrfist]

encountered this on zealot at Aiwella. Especially when we have it cornered and the Mob has nowhere to run.

I hear the hit sound but no damage was registered. Only could damage it when Bleed attack lands a hit.