Every time I visit the backend component it tries to load an image /media/com_cmc/backend/images/cmc-logo.png which doesn't actually exist so it generates a 404 error in the background although the page displays ok.

It is on line 658 in the page source which appears to be part of a survey form that is hidden from view.

I checked the original 4.1.0 zip file that I downloaded from here and the file is indeed not there.