I get this error using Live composer:
Live Composer returned JS error
SyntaxError: Unknown / Unhandled data type(s): "
File “http://localhost:8080/wordpress/wp-content/plugins/live-composer-page-builder/js/builder/builder.plugins.js?ver=1.1.3”, line 294, char 50
The error occurs when I try to set with 4/12 for three different modules. When I publish and save the page, one of the three modules is shown by 12/12 width, and the other two with 4/12 underneath the first one.