2 Potential layout bugs

1. When adding a Container / Grid area, the <div> does not close and contains other fields and elements that come after it.That might cause a layout & JS issues
2. it might be that the fields inside the grid need width:100% in order to fill the 1FR it has.
3. when adding a field-class to checkbox group - the class is being added to both the desired containing div but also to the nested checkboxes container.  Basically, it is impossible to layout checkboxes. 
4. also in email field that has a checkbox right after (photo attached)

1. Container not closing

3. field-class on checkbox group

4. email field that has a checkbox right after 

Found the problem.

Joomla Plugin Email Cloacking.

So if you have an email field inside a Container, you might find that the container's div does not close.

Disable the email cloacking plugin.