You can see the issue on the select fields here:
https://www.concentricbyginkgo.com/k12pilots/
This form is totally unrelated to Ultimate Member.
A form on our site is not an Ultimate Member form. It’s created with a plugin called Forminator. However, Forminator also uses select2 for its select fields, and they’re being affected by the Ultimate Members stylesheet.
In the “Customize Select2 CSS” section of your stylesheet um-styles.css, all Select2 elements are targeted regardless of whether they are within a UM form.