"I actually recently fell off a horse with Kelly [Bensimon], so I'm not going," she announces in the June 2 episode. "I'm very nervous. I don't know if it's that time of month or if I've had too much Moroccan coffee or something."
Though Jill Zarin, 47, isn't too bummed by her costar's announcement ("To be honest with you, I needed someone to take pictures for me," she says), Alex McCord wonders if there's another reason Morgan is forgoing the excursion.
"There are definitely things that Sonja's been doing and saying that seem a little bit strange," McCord, 37, says. "Is there something brewing that we don't know about that's making her act in a way that's a little bit erratic?"
The Real Housewives of New York City airs Thursday at 10 p.m. EST on Bravo.