Click the Backend Divi Builder Settings button. From the Toolset menu, click on Content Templates. Then select a content template from the list. After that, click the "Edit with Divi Builder" button. When the backend builder appears, click the Divi Builder Settings button (the hamburger menu in the purple Divi Builder menu bar). It should open a pop-up containing the builder settings but instead nothing happens. The rest of the Divi builder buttons seem to work, but not that one.
Additionally, this seems to only happen with Toolset Content Templates. If I do the same thing on a page or post, I can bring up the Divi Builder settings with no issues. I'm not sure when this started. There have been some toolset updates recently, as well as a number of Divi updates.
When I bring up the browser dev tools, it appears that when I click that button, it throws a Javascript error:
Uncaught TypeError: Cannot read property 'split' of undefined
at HTMLDivElement.<anonymous> (builder.js?ver=3.21:12982)
at Function.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:2)
at a.fn.init.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:2)
at et_pb_create_prompt_modal (builder.js?ver=3.21:12890)
at N.d.settings (builder.js?ver=3.21:8072)
at HTMLDivElement.dispatch (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3)
at HTMLDivElement.r.handle (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3)
at Object.trigger (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3)
at Object.a.event.trigger (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:8)
at HTMLAnchorElement.<anonymous> (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3)
(anonymous) @ builder.js?ver=3.21:12982
each @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:2
each @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:2
et_pb_create_prompt_modal @ builder.js?ver=3.21:12890
settings @ builder.js?ver=3.21:8072
dispatch @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3
r.handle @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3
trigger @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3
a.event.trigger @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:8
(anonymous) @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3
each @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:2
each @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:2
trigger @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3
(anonymous) @ builder.js?ver=3.21:19172
dispatch @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3
r.handle @ load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-widget,jquery-ui-position,wp-pointer,jquery-ui-core,jquery-ui-mouse,jquery-ui-resizab&load[]=le,jquery-ui-draggable,jquery-ui-button,jquery-ui-dialog,jquery-ui-tabs,suggest,underscore,shortcode,wp-util,quicktags,wp-a11y,w&load[]=plink,backbone&ver=5.1.1:3