OnZOOM Recurring Event - Participant Reminders

I've got a recurring event in OnZOOM. My participants are advising me that they're only getting a reminder for the first meeting after they register, but they don't get one 24-hours before the rest of the series. Is just the one reminder 24-hours before the first class only, the way OnZOOM event reminders supposed to function or is there a problem with OnZOOM where the participants should be getting one before every class but it's not going out like its supposed to?