If WAL replay has been paused (using pg_wal_replay_pause(),
on PostgreSQL 9.6 and earlier pg_xlog_replay_pause()),
in a failover situation repmgrd will
automatically resume WAL replay.
This is because if WAL replay is paused, but WAL is pending replay, PostgreSQL cannot be promoted until WAL replay is resumed.
repmgr standby promote
will refuse to promote a node in this state, as the PostgreSQL
promote command will not be acted on until
WAL replay is resumed, leaving the cluster in a potentially
unstable state. In this case it is up to the user to
decide whether to resume WAL replay.