Will the leader know that the birthday reminder is off?

Yes, as long as it is above the supervisor, it will still be received.

After the enterprise opens intelligent personnel, employees can customize birthday information and turn on and off birthday reminders. By default, it is open. After opening, it will automatically send birthday greeting reminders to colleagues and supervisors in the same department on the birthday. After closing the birthday reminder for colleagues, the supervisor will still receive this reminder. Directly closing the employee care function is not supported for the time being.