It seems this is not an airline glitch, but an Orbitz one, and I imagine it will get corrected as soon as someone books a flight.
There are several more like this in various places around the world. Posting as fast as I can.
Good luck!
Denver to Belize City, Belize plus 8 nights – Mon, Feb 12 to Tue, Feb 20.
Flight Alone: $130 (Check Business Class Fares)
Flight + basic hotel: $420 – Flight plus 4 & 5 star hotels: Click for more details
Not sure if this is the best airfare possible? (Compare historical fares)
Other options: AirBnB or VRBO. Hostels.com or Hostel World.
Know someone in Belize City? Try a reverse-search & invite them for a visit.
All Inclusive Options (if any)
Click here for screenshot of fare found