Failed Impa Spawn
In a recent run, the Weird Egg got randomised into Ganon's Tower. After getting it and finally getting Zelda's Letter, Impa had failed to spawn, even when leaving the room and returning, or entering the castle again, making the vanilla Zelda's Lullaby item source unavaliable. Although this problem isn't run-breaking for this run (the spoiler log says the item was a skulltula token), this bug could possibly make a softlock from losing an important item.
Spoiler Log: OoT_HU75RPBACA3A_2PV63EW5DH_Spoiler.txt
Was this the "Got OoT location before seeing Impa" thing?
Ah, yeah, I had gotten the OoT source. I take it this is a known problem then.