Why are two emails autopopulating when I try to share?

I am trying to add a contractor to a report I'm sharing (Erika), and when I type her email it, it is somehow linked to another email address at that company (a different person, who is also already shared to this report). Both emails pop up in the auto-fill suggestions as if they are one and when I hit enter, only the first one is actually added.

How did this happen (what did I do to cause this), and how can I fix it?

Neither of these people are licensed users on my company's account.

Thanks for your help - Jennifer

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