We are running WPDiscuz for quite some time now, without any issues. Until today where users are reporting they can no longer comment because the submit button is gone. You can check it here for example:
For future reference, after some more troubleshooting, the issue appears to been solved.
JQuery Migrate was being deferred + loaded asynchronously (<script async defer src="..."></script>). WPDiscuz was not liking that apparently. Setting it to only async solved the issue.