CB

If you've an input with multiple remote validation rules (e.g. Code Validation and Query Validation) only the first supplied validation rule will apply. This is due to jQuery Validate not supporting multiple remote validation rules on an input. It's likely this will not be possible to fix as the multiple remote validation rules would need to be combined and ran one after another in a promise object.

https://www.joomlapolis.com/forum/153-professional-member-support/242370-how-can-set-field-value-to-be-uniqe?start=6#318023