Hey Grant,
I have checked your page and I can confirm that the accordion item does not collapse after it expand. Taking a closer look, it turns out that you are using an older version of Pro theme. Pro 1.2.7 is now available in automatic updates! This release contains fixes for several issues so be sure to check out the changelog (https://theme.co/changelog/). Please do update to the latest version. After doing the updates, always remember to clear all caches when updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
Please let us know how it goes.