Hi ​@Cris80206. This does sound like aberrant behavior. I’m assuming this is a workflow attached to a Group Event type. First thing that comes to mind, if this was a meeting that was rescheduled by the invitee and they used a different email when completing the new booking that could look to Calendly like a separate person altogether. Outside of this scenario I am having trouble replicating this issue. If you are on a paid plan then you might want to reach out to our customer support team as they can diagnose your issue live via chat → Contact Customer Support

Thanks Sean. It’s not just SMS notifications, it also happens on email notifies. 

I will reach out to support.