Cloning a Metabox Group item results in 'property content is undefined'

Hi,

I’m trying to clone a Metabox Group item but the Javascript fails as a result.
Output:
Uncaught TypeError: Cannot read property ‘content’ of undefined
at Object.group.toggle.updateTitle (group.js?ver=1.1.2:65)
at HTMLDivElement.group.clone.processGroup (group.js?ver=1.1.2:257)
at HTMLDocument.dispatch (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:3)
at HTMLDocument.r.handle (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:3)
at Object.trigger (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:3)
at Object.a.event.trigger (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:8)
at HTMLDivElement.<anonymous> (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:3)
at Function.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:2)
at a.fn.init.each (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:2)
at a.fn.init.trigger (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-position,moxiejs,plupload&ver=5.2.1:3)

This error occurs in the group.toggle.updateTitle() function in group.js on line 65.

Is this a known problem and what can I do about it?