Can't add custom CSS or ID to text block element

We’re running the latest version of Enfold (4.6.3.1) on multiple websites and have found that we can’t add custom CSS classes or IDs to the text block element.
Custom IDs and CSS Classes have been enabled in the Enfold settings and are working for other element types, however when you switch to the “Developer” tab when editing a text block element the fields do not show.
Adding a class parameter to the shortcode using the shortcode debugger doesn’t work either, it strips the value from the class parameter.
We’ve always used custom classes for text blocks, so this must be a bug.