Shadows Blur Together achievement not working?

[Noods]

After hours of grinding, one of my infected Vestals struck another Vestal and killed it. The achievement didn't pop. Is this achievement bugged? Is there something I need to do to get the game client to recognize it?

[Álcool Isopropílico]

The attack trigger was a bloodlust or an afliction?

[Noods]

Don't recall. From what I read everywhere, it didn't have to be a bloodlust. Most posts said it just happened more frequently in bloodlust. Does it have to be bloodlust?

[Sir Francis]

Obviously yes, regarding your observations.
heres a link to my guide: http://steamcommunity.com/sharedfiles/filedetails/?id=1123693730

[Álcool Isopropílico]

It has to be a Bloodlust trigger. An Abusive trigger don't work. I guess this was the problem.