translated Custom field url ( when filtering )

I have a custom meta box in taxonomy.

this meta box has a select option meta field of months 

this is translated to the second language with polylang string translation

I then use this month selection in the term, to filter posts 

it works in the first language, but in the second language, the front end “select” filter, gets populated by the translated values ( months ), but the url im getting when im choosing a month, is the first language, untranslated name.

do I need the pro version for this ?

thanks