Same happening for me on Windows 7/Chrome browser…
Nevermind, I figured it out…
I had this line in my functions.php. It had to be removed before deactivation:
remove_filter( 'the_content', 'nrelate_related_inject', 10 );remove_filter( 'the_excerpt', 'nrelate_related_inject', 10 );add_filter( 'the_content', 'nrelate_related_inject', 99 );add_filter( 'the_excerpt', 'nrelate_related_inject', 99 );