I'm toward the end of the main story, and am just really confused about something, based on having done some things out of order. I got Mineru's mask and did the construct factory before going to the castle, and so after doing the castle they try to prompt me on my big quest to find the fifth sage and then are just like "oh wow you already found her, ok I guess you can just go try to find Gannondorf now."
The weird thing then was I immediately go to talk to Purah again and she says again (paraphrasing) "Ok, now you need to go find Gannondorf." But it then showed the Link talking animation, and Purah says "Oh you found him already? He's in the Depths? Go tell Josha." I talk to Josha, and she's like "Oh wow, you found him! My work paid off, yay!"
What's confusing is that I have no idea what I did to trigger that interaction. I had never had any opportunity to talk to Josha about Gannondorf, and as far as I know I have not actually found him yet (in the game at least--it's no real surprise where he is). I have not been into the chasm under the castle, nor into the part of the Depths anywhere near there.
There's either something I did ages ago that I don't remember, or it triggered just based on getting close enough to the chasm for it to mark on the map, or it's a logic error in the game, but it's very bizarre.