Stripping out Div Issue on List items

One line 132 of megamenu.utilities.inc in the current developer edition:

$output = substr($output, 0, strlen($output) - strlen('</div>'));

This is causing major levels of broken-ness in a site that worked with a dev from 2013.

This is the offending line and used to be:

$output = str_replace('</div>','',$output);

I think this needs to be refactored at some point, but I'm thinking others may be having this issue also.