Custom HTML?

Hi,

How can I add a custom HTML after the replay button?

I use this filter, but when I added it in function.php the comment form is not loading anymore.

add_filter('wpdiscuz_after_reply_button', function ($html, $comment, $user, $currentUser) {
    $html .= '<a href="#">Link</a>';
    return $html;
}, 10, 4);

Also, I see the following error in the console:

wpdiscuz-combo-no_quill.min.js:6
SyntaxError: Unexpected end of JSON input
    at parse (<anonymous>)
    at jquery.min.js:2:79470
    at l (jquery.min.js:2:79587)
    at XMLHttpRequest.<anonymous> (jquery.min.js:2:82355)

`

wpdiscuz_after_reply_button works only if I added non-HTML content, like as:
$html .= ‘some content’;

Thanks,
Alex