I began testing the beta version of the Linux controller back in July of this year, and since then, I have not received any forwarded syslog messages to my Graylog instance.  No relevant settings or configuration were changed on either the controller or my Graylog instance.  I wanted to check whether are any known issues with syslog forwarding in the beta versions of the controller.  I just updated to 5.14.32.2 and the behavior has remained the same.