Wocommerce search by attributes not works fine : i developed a search by attributes in woocommerce and everything be ok. But one attribute not work in the search. The only difference that i find is that is an alphabetical attributes and the others are numeric.

For example the url

http://neumaticos.7vidas.com.ar/?s=&post_type=product&product_cat=neumaticos&categories=neumaticos&pa_vehiculo=&pa_ancho=175&pa_talon=&pa_rodado=

returns the correctly results but when i search by vehiculo (pa_vehiculo) returns all the products.

Someone know what can be happen?

Thank you!