Having read the code, I now understand that the checkproc failures are actually expected. Even if I delete agent.info, I guess the agent.info-endymion:0 check would fail too after a reboot, as a new gpg-agent process has to be started at that point. So most likely the real fix here would be redirect checkproc's stderr to /dev/null so that the error messages don't get logged. Why journalctl only shows the first error when I'm not root would be a separate issue.