Reply To: "loyal" filter – mail to client after admin edit

The loyal filter works pretty basic. What you have defined is essentially “when there’s 1 approved reservation by this email apply this filter” what it does. That’s a problem of the prices getting calculated live, you would have to fix the price of the old reservations (and raise the condition to two) to only make it affect new ones.
For the admin by email it has to be activated in the email settings and when editing the checkbox to send a mail has to be checked.