Just in case somebody need it:
wp-includes\classes.php
line 621
comment or remove these lines
if ( $use_desc_for_title == 0 || empty($category->description) )
$link .= ‘title=”‘ . sprintf(__( ‘View all posts filed under %s’ ), $cat_name) . ‘”‘;
else
$link .= ‘title=”‘ . attribute_escape( apply_filters( ‘category_description’, $category->description, $category )) . ‘”‘;