From what I understand the Alpha schedule synchs up with the Appointment Plus booking system approx 8 pm Sunday night.Best to book late on Sunday or later in the week.
Other spas use the same booking system. I booked appointments at other spas only to have the appointments disappear when the system synched. Wasn't too happy about the situation but that's life.
The spas are very good at reaching out when issues occur and making adjustments. Or, in my case at another spa, was told that's the way it is. Best to contact reception or management directly and they'll make amends or not.
Nothing is ever perfect as we're dealing with complex human and technological interactions.
Sometimes TGTBT is TGTBT. It all works out in the end