@Ahmed5 You are correct. This is very odd since your listing description says minimum 1 night stay as well as your calendar. I would try going to your Availability Settings and changing from one to two nights, save (if not automatic) and the reset to 1 night minimum. If that doesn't fix things, call Airbnb to have them take a look at your settings at their end. Here's how to contact Airbnb:
https://community.airbnb.com/t5/Tips-Tricks/Contact-Airbnb-A-Community-Help-Guide/m-p/16165/highligh...
I find Twitter @airbnbhelp to be the fastest way to get help. Please get back to me a let me know what the solution turns out to be!.