URL rewrite breaking pagination

This works: mysite.com/sermon/term/childterm/page2/

This does not: mysite.com/sermon/term/childterm/page2/

according to your rewrite rule, I guess what you mean is

This works: mysite.com/sermon/term/page2/

This does not: mysite.com/sermon/term/childterm/page2/

I’m not a regex expert so I only come up with adding another rewrite rule to handle the
childterm situaion

add_rewrite_rule(
        'sermon/(.*?)/(.*?)/page/?([0-9]{1,})/?$',
        'index.php?post_type=".$cpt."&'.$tax.'=$matches[2]&paged=$matches[3]',
        'top'
    );