pacemakerd continually monitors subdaemon IPC by trying to connect to it. However after pacemakerd sends SIGTERM to a subdaemon to initiate shutdown, it should stop that monitoring, because the daemon will stop accepting IPC connections:

Dec 12 11:29:01 rhel8-1 pacemakerd          [65317] (stop_child)        notice: Stopping subdaemon pacemaker-based | via signal 15 to process 65321
...
Dec 12 11:29:04 rhel8-1 pacemakerd          [65317] (check_next_subdaemon)      notice: Subdaemon pacemaker-based[65321] is unresponsive to IPC after 1 attempt (will recheck later)

Or perhaps better, continue the check, but if we know the subdaemon is shutting down, log a better message such as Subdaemon pacemaker-based[65321] has stopped accepting IPC connections during shutdown.