We do experience the same issue running the latest version from backports (8.23.0-2~bpo8+1).
Rsyslog without TLS is stable, with TLS we are getting hang on higher amount of messages (120.000.000 per day, not sure about the peak value during the hang). Process stucked in sleep state - consuming one core for 100%. Strace on the process showed some timeouts. Let us know what information could help us to find the root cause. -- Peter
