"I'm not sure if it's just a simple matter of amnesia. Kya anticipated that Korra's recovery could take weeks, if not longer. And yet here she seems to be in perfect condition, with no recollection of the poison or most the battle..."

Lord Zuko lapses into silence as he mulls it over. Why are some affected by the changes, but not others? It could have been the spirit world's way of helping Korra back on her feet, but even so...

He lowers his voice over the chatter and music as much as possible, so as not to be overhead. "There are some here that seem to have been pulled by the spirit world out of the past. I wonder if Korra and your brother follow that same pattern." Even if their 'past' isn't as far back as the end of the Hundred Year War, like many, it would still explain the discrepancy.