I have a similar issue with ACF 4.4.3 in a WYSIWYG field in a custom taxonomy – the text tab does not display and a JS error is thrown.
I turned on script debug, and the error for input.js occurs on line 199, where it looks like the script is parsing the URL.
There may be a bigger issue behind the non-rendering – I have a WYSIWYG field in a repeater on a page using a custom template. The text tab is not shown for that field, but there is no JS error in that instance.
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