Use of indirect object pronoun

Use of indirect object pronoun
 

Today (June 6) I read this in Noticias Caracol (Colombian news online):

"La mujer le narró a agentes del FBI lo que sucedió ..."

I would have thought that the indirect object pronoun in this case would be plural, les, to agree in number with agentes.

Is there something that I am missing regarded the rules for agreement in number of indirect pronouns with their nouns?

Thanks.

Yes, the plural indirect object pronoun should have been used. What you've run into is either a typo or a grammatical error.
Grammatical errors are made all the time, in all languages. ;)

Same case as "le echó el ojo a las uvas". ;)