Hi CfAllie! The mystery is solved, sort of. I found the offending form submission. Have you ever heard of autohitsite.info? Somehow, they are filling out my form with a bunch of weird data.
Additionally, they have answers for select box fields that are not part of the select box answers.
Also, the URL that they are coming from is not the one that calls our form.
I'm relieved that my form works, but not sure how they are submitting this strange data.
Thank you for all your help!