You know, that's a very good question. Outside of the scene in which Claire waves to Quentin when she finds him outside the cemetery and then the scene at the Jenkins cottage, Claire and Quentin never really interact. You're right that their relationship doesn't come close to the genuine connection between Claire and Tracy.
Now, there is a bit in the script during the cottage scene where Claire kisses Quentin and says, "Lovely having you here," but that was dropped in favor of Claire simply saying something completely innocuous about lunch, so as the film stands in the cottage they don't interact at anything but a surface level. I wonder if that was a decision made to reinforce that Claire still hadn't bonded with Quentin in a way what was dropped could have indicated? I suppose only Nancy Barrett herself or her NoDS script could answer that if she indicated why the change was made, but I've never seen a copy of her script.