I personally have had this issue, and as a tournament director I am seeing this as well. There are multiple judges (who presumably don't have accounts - I'm not sure on that one) who have been linked to another account/email. In the current tournament I am directing, there are SIX different judges from different schools across the state of KY who have this linked account: firstname.lastname@example.org (and the phone number is a Philadelphia area code)
In my personal instance, I could not see this link on my roster, but when I went into my tournament entry I see the link. A coach who is not double-checking their judge entries wouldn't notice, assuming that their judge is linked correctly.