For Marta Harnecker, here are the values:
author ID: 186
term ID: 390
The post ID that this coauthor should be linked with is 393. When I search for this post ID in terms_relationships-->object_id, I get the following term_taxonomy_id's. I've listed their relationships in parentheses:
3 (post type), 11 (category), 37 (category), 388 (tag-chavez), 389 (author-chavez), 390 (tag-harnecker), 391 (author-harnecker)
The only difference with the repeated authors is that one is an author and the other is a tag. So, term 390 has the values:
name: Marta Harnecker
And term 391 has the values:
This is because for all posts we made sure to add the author names as tags as well as coauthors, in case something like this happened. Regardless, this coauthor should be linked with this post but it is not.
One other thing I should mention, though it should not matter, is that I do not use the default prefix.