Thrasher Terror Howl Bugged in 6/4man

[Yukimisama]

I'm a Blade Master and I have the siren belt equipped and have the unphased buff. However, even without poison I am still taking the howl damage. I understand you can get poisoned and then take the damage even with the unphased buff, however I'm able to reproduce the bug every single time, without fail on my character, even if I go hide in a corner and take 0 poison for the entire rotation, I will still eat the howl damage after he gets up. My Blade Dancer/Destroyer friends do not have this issue and they do not use the soulshield, they use the belt, It may be a class specific thing to Blade Master

[Samyaza]

There are several tipes of poison, one of them which triggers howl dmg is the 1 minute duration one, which you need to cleanse in the falling water. Are you sure you are removing this one, since you didn't mention it?