Your booking calendar lets guests select a stay shorter than the minimum nights shown on a listing.
Why this happens. The date picker enforces the minimum stay that your PMS sends for each listing and date. Labels or tags on a listing are display text only and do not set a minimum. If your PMS sends a one-night minimum for every date, the calendar has nothing to block, and any stay length can be priced.
What you can do. Set the minimum nights on your listings inside your PMS. In Guesty, you do this in each listing’s availability or pricing rules settings. Once a minimum is configured there, the calendar refuses check-in and check-out selections that fall short of it and shows your guest a message such as "this home requires a 2 night minimum". You do not need to change anything on the website itself.