Yes very frustrating! I've reported a similar glitch to airbnb twice. I think it might be a problem with the phone version of the app. When I add or edit the Availability Settings with the app on my iphone, it changes ALL of my other settings so that the check box is checked "Guest must arrive on a specific day" and sets it for "Monday".
I've reported this problem before, and noticed that it *seemed* to finally be fixed. Today I updated a few settings and it looked perfect in the app on my phone (I checked it twice to be extra sure). But then I decided to also take a look with the full desktop version on my imac and sure enough, ALL of the settings had changed with the little check box checked once again. So from now on I'm not going near those settings with the iphone app!
I'm posting this here with the hope that other hosts will also report this problem to airbnb. Of course many hosts could go for weeks or even months without getting any new bookings and have no idea why...
