I just got the house from JKK, and when I selected "That is superb! But let me ask you something else before I leave" when Ola tells me the details, the conversation topics change to the topics he had in the sewers during the warehouse mission, complete with the closing dialogue of that thread, with "Me, fail? *laugh*", and him telling you to watch out for Vivian.
It's not a gamebreaker. Once the dialogue closes and you talk to him again, it's just the barter and exit option there.
