After finishing Finding Kara, I was able to go to the basement and do the abbess's bossfight. After completing it, it immediately showed me the cutscene with Kara, Therese, and Magda, after that I got the mission, Kill Reignvoldt. At this point most of the Cathedral (aside from Magda's path) was still inaccessible. However after reaching the Cathedral, a cutscene played and skipped me to the Angel boss fight. At that point I tried to load a previous save from before Finding Kara, but when I did the game was still in a state where Kill Reignvoldt was active. Kara and Therese were not in their usual places, and I wasn't able to access Olivina as an NPCs.