Game Mechanics: Not Able to Use Invis Potion While Trading

[Ananka]

I've been doing the Note to Neclo Quest in Qeynos Hills the past couple days and today I hand over the note but I cannot click a cloudy potion while trading. This is about the only way to start working on Order of Three faction when you're extremely KoS. I was able to use a cloudy potion then click trade yesterday but not today. I've reset my PC but it's not on my end. I can right click potions any time except during trade today. I've even killed off Neclo to reset him but I'm still stuck.