We are experiencing an issue in the appointment module (Odoo 17). Despite setting fixed time slots with resource restrictions, double bookings can still occur. I suspect this is caused by the additional time slots we added via "Extra Availability." It seems that these extra time slots remain open at all times, even when the assigned person or location is already occupied. This appears to be a hierarchy issue in the availability rules.

We are unable to resolve this. Additionally, our former implementation partner added custom programming. Can I remove this without affecting Odoo itself?

Any help is greatly appreciated!