Multi Select Not Updating Custom Taxonomy

I have a multi select field that’s being populated by a custom taxonomy. The form is set to create a post upon submission, however when it does, it only saves one of the terms I have selected in the multi select field. In other words, it is updating, but not updating all of the selections. It only adds the first selection alphabetically. So if I selected Music, Art, and History as my terms it will only save Art and nothing else. I tried with checkboxes and that saves them all, but I have a lot of choices and don’t want a large list of checkboxes on my form.

https://wordpress.org/plugins/gravity-forms-custom-post-types/