HTML characters broken in accordion title

First : how do you insert that registered mark to your title. Copy paste from an existing one – or do you use a html entity?

Sorry – my code had to be updated with vers. 6 – …
please try on child-theme functions.php:

function wrap_copyright_text_with_sup(){
?>
<script>
(function($) {    
	$(window).on('load', function(){
		 $('body :not(script)').contents().filter(function() {
			return this.nodeType === 3 ;
			}).replaceWith(function() {
				return this.nodeValue.replace(/[™®©]/g, '<sup>$&</sup>');
		 });
	});	
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'wrap_copyright_text_with_sup');

But i do not know why on toggle titles this happens twice. …
maybe a mod knows why – guess it has to do with the way the opended toggle Title is set.

hm – even after replacing all files the script does not work on toggle titles as expected.
See on headings and in text block alb all is ok.
https://webers-testseite.de/accordion/

Edit : i removed the script to show that the fix is working on toggle titles

But did you try to use now the tags as before? as far as i understand he fixed it.
my solution is something if you use many of them and want to wrap all at once in <sup></sup>
that warning comes always – when using tags.