I'm not so sure about this. I haven't watched any of these episodes in nearly two years, but I don't remember Barnabas ever being so totally weird again after that scene in the Old House - correct me if I'm wrong. Vicky tended to get split off into the Jason plot, so it seems to me she didn't see too much of Barnabas for a while. Memories fade and their edges wear down, and after a few more encounters with Barnabas in which he seemed simply old-world-Continental as Carolyn had asserted, it would be reasonable for Vicky to feel that her first impression of Barnabas was a little bit off, and that any oddity she had observed was due to his being uncomfortable with strangers, and that he was OK after all, and his peculiarities were no big deal.