There is a bug with minus accuracy effects during the Beastmoon event that's been going on for a while now and I've not seen KI try to fix the problem. When a minus accuracy hanging effect is placed on a target, there is a chance the effect will trigger twice; once after the initial placement of the effect and then again the following round (or whenever that target attempts to cast another spell).
I just lost a match because my teammate had an accuracy depuff placed on him that caused his next spell to fizzle (50% chance) and then again the following turn. The first fizzle happened the correct way; the minus accuracy hanging effect was present around his head and triggered like normal. The next round, my teammate had no visible minus accuracy hanging effect, nor did our opponent cast another accuracy debuff, yet the trigger went off and my teammate fizzled his spell for a second time in a row.
This is a huge bug that needs addressing. It's not something players can control or abuse, but it's unfair when it does happen. It happens during both PvP and Mayhem modes, the latter mode being especially annoying since we struggle enough with fire enemies eating up our time through dots - we don't need their accuracy debuffs triggering twice either.
This glitch seems to happen most often when a mantle is placed on someone with a blade. Worse yet, it works with Dispels too.
I hadn't encountered it consecutively enough to notice a pattern; thanks for the info! And yes, after doing some digging through the forums, I've seen others commenting that this bug works with dispels too, which is very frustrating.