Customiser little JS problem.

Hi
We have a little problem with customiser on version 3.2.9 (we can’t do the new update yet)
On somme blogs (multisite) we cannot go back when we are on Global Settings / General design options. We have to close the customiser and come back. Only this part of customiser make problem which occurs both on our child-theme or the master theme.

czr-control.min.js?ver=3.2.9:11
 Uncaught Error: prepareitemForAPI : a item must be an object to be
 instantiated.

 prepareItemForAPI       @       czr-control.min.js?ver=3.2.9:11
 instantiateItem @       czr-control.min.js?ver=3.2.9:11
 (anonymous function)    @       czr-control.min.js?ver=3.2.9:11
 m.each.m.forEach        @       load-
 scripts.php?c=1&load[]=underscore,shortcode,utils,jquery-core,jquery-
 migrate,backbone,wp-util,…:5
 populateSavedItemCollection     @       czr-control.min.js?ver=3.2.9:11
 (anonymous function)    @       czr-control.min.js?ver=3.2.9:11
 i       @       load-scripts.php?c=1&load[]=underscore,shortcode,utils
 ,jquery-core,jquery-migrate,backbone,wp-util,…:10
 fireWith        @       load-
 scripts.php?c=1&load[]=underscore,shortcode,utils,jquery-core,jquery-
 migrate,backbone,wp-util,…:10
 e.(anonymous function)  @       load-
 scripts.php?c=1&load[]=underscore,shortcode,utils,jquery-core,jquery-
 migrate,backbone,wp-util,…:10
 ready   @       czr-control.min.js?ver=3.2.9:11
 (anonymous function)    @       czr-control.min.js?ver=3.2.9:13
 i       @       load-scripts.php?c=1&load[]=underscore,shortcode,utils
 ,jquery-core,jquery-migrate,backbone,wp-util,…:10
 fireWith        @       load-
 scripts.php?c=1&load[]=underscore,shortcode,utils,jquery-core,jquery-
 migrate,backbone,wp-util,…:10
 set     @       load-scripts.php?c=1&load[]=media-editor,media-audiovideo
 ,mce-view,imgareaselect,image-edit,customi…:6
 d       @       load-scripts.php?c=1&load[]=underscore,shortcode,utils
 ,jquery-core,jquery-migrate,backbone,wp-util,…:10
 _toggleExpanded @       load-scripts.php?c=1&load[]=media-editor,media-
 audiovideo,mce-view,imgareaselect,image-edit,customi…:8
 expand  @       load-scripts.php?c=1&load[]=media-editor,media-audiovideo
 ,mce-view,imgareaselect,image-edit,customi…:8
 (anonymous function)    @       load-scripts.php?c=1&load[]=media-editor
 ,media-audiovideo,mce-view,imgareaselect,image-edit,customi…:8
 dispatch        @       load-
 scripts.php?c=1&load[]=underscore,shortcode,utils,jquery-core,jquery-
 migrate,backbone,wp-util,…:11
 r.handle        @       load-
 scripts.php?c=1&load[]=underscore,shortcode,utils,jquery-core,jquery-
 migrate,backbone,wp-util,…:11