I’m not sure what “This” refers to here, but the fact that a client that stops reading its notifications will prevent notification delivery for other clients - described in @oak’s original post, but now removed by an edit - is a known side effect of intentional design, see Improving performance of notification streams. The failure to create a new subscription in this scenario sounds like a bug, though.
Right - since the reported PID of ConfD changes between those entries, it definitely did restart:
1-May-2019::19:20:45.604 confd[1604]:
2-May-2019::00:13:29.195 confd[1590]: