If I open https://pt.wikipedia.org/wiki/Exponencial_matricial and click on the video, then close it, the following error message appears in the console (using Firefox):
{ "errorMessage": "Error: cannot call methods on slider prior to initialization; attempted to call method 'value'", "url": "https://pt.wikipedia.org/w/load.php?debug=false&lang=pt&modules=jquery%2Cmediawiki&only=scripts&skin=vector&version=YnvhQe2A", "lineNumber": 3, "columnNumber": 612, "errorObject": {} }