Thanks for finding this Laine! I posted an update to the repo that should work now.
Basically I added a few lines to sort the object alphabetically before displaying it each time to avoid the issue 🙂
Can see the specific fix here:
https://github.com/zgordon/gutenberg-course/blob/bc3dbbe20b72c3cf24ff767650ae0d0271cfae4f/blocks/07-inspector-control-fields/index.js#L15-L25
Let me know if you have further issues! I will add a note to the video with this thread 🙂