Quotes being added to mapped fields, creating single taxonomy term

I'm trying to map the following to a Taxonomy field:

[options] => Array
        (
            [original_author] => Array
                (
                    [name] => Person1, Person2, Person3
                    [link] => 
                    [email] => 
                )
)

Using SimplePie and the Exhaustive Parser, in the mapping options, I can map the options->original_author->name: to a taxonomy field, but the result is "Person1, Person2, Person3" with the quote marks *included*. This means that rather than 3 taxonomy terms being created, a single term is created.

At what point are these quotes being added? I have the taxonomy field set to tags and multiple select.

I know this is possible as I had it working until recently on my dev site, but I've no idea what change I made to cause it to stop working.