Availability settings: Advanced notice same-day booking time -- re-set automatically to midnight

[Rob-and-Patty0]

We have 3 units on Airbnb.  We set same-day booking limit to 10AM on all 3.  Last night, 2 of our places instant booked at 5PM and 8PM for same-night stay.  With hundreds of bookings over the years, this event has not happened before -- and last night it happened twice.  While the bookings are appreciated, the surprise factor is not.  I found the settings for same-day booking at midnight.  I recall setting those to 10AM, though the setting is buried so it's not something I regularly review.  Have other hosts experienced this?

[Kari6]

I had this happen the other night.  I had mine set at 7pm and only by accident checked my phone after a personal call to Fund someone had instant booked and was on the way 8:30pm asking for the door code.  I checked to make sure it was set right and was confused that I was caught so off guard 

[Diane461]

What is advance notice? I did not put it there but it is on my calendar 

how do I remove this? DiV