Well first of all congrats on getting this project finished (Any bugfixing left aside.). Sorry if this isn't very helpful but of the three times it happened the first I didn't notice anything (This was a fresh save I'd started tonight.), the second (It's this save
#12,275 in case you want it as a guinea pig) I was obsessed with beating the ghost girl and had just walked into the next room to save when I noticed, I was doing a lot of resetting so that could be something to look into, the third time (Same save as the second.) I beat her had saved and then progressed with the girls that the user whose save I was using hadn't worked on I noticed a few times the lighting went yellow tinted and then fixed itself before I ran into the Kaylee bug and when I went to reload it was empty. On all three I had used rosebud and for the save I got from here I used whoami to rename myself.