This issue might happen when you have a lot of locations or agents and your PHP limit set for max_input_vars directive is not enough to handle form submission, If there are more input variables than specified by this directive, an E_WARNING is issued, and further input variables are truncated from the request. For more info click here. Your hosting company can assist you with increasing it, you can set it to 2000 or higher if needed.

To debug this and other possible issues we strongly recommend enabling debug mode when testing, to check if there are any other errors.