I updated my code so that the validation rules are a parameter of the Metabox and not the fields. I also updated the metabox plugin validate.js file to reflect the changes.
I also confirmed that Metabox and all other Metabox.io plugins are up to date.
I am still getting no validation.
A couple of things to note:
1. The required symbol (*) is now displaying – it wasn’t before.
2. After this change, the required attribute no longer works.
There are no errors in the console.
Let me know what more I can do to be helpful.