so it's not clear in game, but soul renderer checks for each individual debuff. so poison is always a single debuff, but somethings such as Pyris Ignite each hit does a separate debuff. In general though most effects count as 1. As for karakai i dont have my computer for abit so i cant check specific numbers but depending on the order the effects trigger acuity can activate first filling your mana then vortex increases your total so you need to gain a bit more mana to actually cast the 2nd time. I believe vortex is +10 each cast, including the extra cast acuity causes.