The order of the validation error messages varies depending on the method used to make them Required.
The behavior method
This method will depend on which order the Required fields were selected as Required.
Required properties on the form field
This method will generate the validation error messages from top to bottom, regardless of the order in which the fields’ Required options were selected.
If both Required methods are used, it will execute the validation in the order selected from the Behavior tab first, then execute the validation from the form field for the remaining fields.