This one isn’t hbs related. It’s related to resolver-resolutions:
You can always find more information about the issue in the browser console.
The problem is in the discourse-category-custom-fields plugin, so you’ll need to report the problem to the author. It is a little strange, because that plugin looks like a test demonstration, rather than a real plugin. Are you sure that you need it on your site? If not, uninstalling it will solve the warning banner.