Vaal Cyclone does not trigger Cast on crit

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nefczi написал:

I also have it linked with CoC and Discharge. When it works its amazing, but sometimes it just doesnt trigger coc at all for the whole duration

Like all skills, it rolls crit once, for the entire skill use. Thus either it will crit every time, or not at all (unless specific enemies have extra crit modifiers on them, such as critical weakness). If the crit roll it makes for that skill use isn't a crit on your weapon against the relative enemies, then that entire use of the skill can't crit.