Never mind - it's adding threads, but they're not visible. Also generating this:
[02-Mar-2021 17:33:30 UTC] PHP Fatal error: Uncaught --> Smarty: Unable to load template 'file:not_right_bare.tpl' <--
thrown in /home/public_html/forums/libs/smarty/sysplugins/smarty_internal_template.php on line 195