Version: 0.21.2 (The download link from the OP post on page 1)
The goddess had just ordered me to go get a female from the base camp, but when leaving her throne room, instead of going left, I went right and into the breach room. I don't have a save from right before this anymore so I can't test it without restarting the whole game, but iirc: I touched the breach for the first time to crack it, then i walked across the spikes because I had the heels, tried to get the necklace but couldn't, went back out, then I solved the lever puzzle before trying to leave, because I didn't know that all it did was lower the spikes. (also I solved it through trial and error because I didn't notice the hint tablet on the wall haha) Then when I tried to leave Kathleen said she might as well grab the necklace, but the handmaiden outfit prevents picking it up.
I'm no programmer, but I'd guess maybe it's because I solved the lever puzzle, and that set a flag to keep Kathleen in the room until she had the necklace?