It would appear that Infinite SEO has a script conflict with Shortcodes Ultimate (specifically with the Maker add-on for Shortcodes Ultimate). From looking at the result of the conflict, it seems that the conflict may actually be between Infinite SEO and the Ace editor (which Shortcodes Ultimate uses). Here is the error I get when looking at the console (in Safari):
[Error] TypeError: 'undefined' is not an object (evaluating '$('#title').val().length') checkMainTitleLength (wds-metabox-counter.js, line 25) setUpCounters (wds-metabox-counter.js, line 64) (anonymous function) (wds-metabox-counter.js, line 68) c (jquery.min.js, line 4) fireWith (jquery.min.js, line 4) ready (jquery.min.js, line 4) q (jquery.min.js, line 4)
If you'd like access to an install where both plugins are present, just let me know and I'll send credentials.