The sauna event is unrelated to Ashley's story, but it leads to the first Sunday lesson with the two of them, and that only makes sense if Ashley's story has progressed to a certain point. The weird issue I'm experiencing is that I'm getting invited to the lesson when I've got nowhere near far enough with Ashley for it to make sense. From what people are saying, the game shouldn't be triggering this until Ashley's numbers hit a certain point, but I'm getting it early for some reason. It's not a big deal as I can go back to my Sunday save and wait to do the lesson until the correct point in the story, but I can't help but be curious what caused the game to break this sequence.