@Carlos1002 You are not understanding. Ignore the wording "one day before and after"- it's very confusing. That setting only blocks one day between bookings, not 2. In the screenshot you posted, yes, it looks like it had blocked 2. But it didn't.
Jennifer booked the nights of the 16th and 17th. Adrian booked the nights of the 20th and 21st. The 19th couldn't be opened up because if someone had booked the night of the 19th, you wouldn't have had one day prep time before Adrian arrived.
I have no idea when these guests booked, but for explanation purposes, I'll pretend that when Jennifer booked, all the dates after her booking were open except the night after, the 18th. The 19th and after would have shown as open for booking on your calendar. But because Adrian booked the 20th and 21st, the night of the 19th can no longer be available if you want one day prep time between bookings. If it was,, the guest who booked the night of the 19th would be checking out on the 20th, and Adrian would be checking in that same day.
(BTW, I stayed in Mazunte almost 50 years ago when there was nothing there but a little rustic sttore that sold coca cola and a few canned goods. The turtle factory was still in operation. I camped on the beach there for 3 weeks.)