Red Hat Directory Server replication Incremental protocol: event update_window_opened should not occur in state wait_for_changes

Issue

When using replication with the Red Hat Directory Server / RHDS, the following error log message entry may appear:
Example from RHDS-10 / 389-ds-base-1.3.9:

[21/Jan/2020:00:00:00.029152517 -0500] - ERR - NSMMReplicationPlugin - repl5_inc_run - agmt="cn=m1 to m2" (ca1:389): Event update_window_opened should not occur in state wait_for_changes

Example from older versions, RHDS-8, 389-ds-base-1.2.11:

[07/Jul/2011:12:11:27 -0400] NSMMReplicationPlugin - agmt="cn=m1 to m2" (ca1:389): Incremental protocol: event update_window_opened should not occur in state wait_for_changes