OCPBUGS-43715: Added IPsec enabled node known issue to RNs

Author: dfitzmau

release_notes/ocp-4-16-release-notes.adoc

@@ -3224,6 +3224,8 @@ In the following tables, features are marked with the following statuses:
 [id="ocp-4-16-known-issues_{context}"]
 == Known issues
 
+* A regression in the behaviour of `libreswan` caused some nodes with IPsec enabled to lose communication with pods on other nodes in the same cluster. To resolve this issue, consider disabling IPsec for your cluster. (link:https://issues.redhat.com/browse/OCPBUGS-43715[*OCPBUGS-43715*])
+
 // TODO: This known issue should carry forward to 4.9 and beyond!
 * The `oc annotate` command does not work for LDAP group names that contain an equal sign (`=`), because the command uses the equal sign as a delimiter between the annotation name and value. As a workaround, use `oc patch` or `oc edit` to add the annotation. (link:https://bugzilla.redhat.com/show_bug.cgi?id=1917280[*BZ#1917280*])