Hi, We use the TLS server as well, and are bothered by the same problem. After installing pgbackrest package updates across out servers (we use the PGDG repo), we experience lots of [ProtocolError] errors on log archiving and backups due to the services still using the old pgBackRest version (having not been restarted).
In my limited testing, simply changing the dh_installsystemd invocation in debian/rules from: dh_installsystemd --no-enable --no-start to dh_installsystemd --no-enable --no-start --restart-after-upgrade fixes the issue. Kind regards, René Højbjerg Larsen, JFM P/S