Service scheduled through bookings page still shows as available time for other customers

I'm making some tests in Bookings and when a customer books an appointment through bookings service page, the time booked still shows as available for the next customers that try to book an appointment too, which can cause a double booking on the same time.

For example, the customer scheduled a booking to September 15, at 11 AM.

But when another customer access the bookings page to schedule, the September 15 11 AM is still presented as available, even though it was already booked.

I confirmed that at my Outlook calendar the appointment is presented as Busy, but Bookings don't seem to recognize its own appointment as Busy.

It's important to say that I already marked the "Events on Office calendar affect availability" for all staff. I also tried to unmark it, save the setting and then mark again and save again. Still doesn't work.

I also checked the timezone for my calendar and the booking page. Both of them are in the same timezone.