Unexpeted warnings in running EAP 7.2 ha-singleton-service QS against EAP 7.3.0.GA-CR1

We run 7.2 Quickstarts against latest EAP release for backwards compatibility testing - all applications that run with EAP 7.2 must run with EAP 7.3 in the same way. There are some new unexpected warnings in EAP 7.2 ha-singleton-service QS run against EAP 7.3.0.GA-CR1 server. These warnings are not present when running the QS against EAP 7.2.0.GA server.

Configure a Random Election Policy part of the QS readme:
server2:

WARN  [org.wildfly.clustering.server] (ChannelCommandDispatcherFactory - 1) null: java.lang.IllegalStateException

Configure a Quorum for the Singleton Policy part of the QS readme:
Both server1 and server2:

WARN  [org.wildfly.clustering.server] (LegacyDistributedSingletonService - 1) WFLYCLSV0013: No node was elected as the singleton provider of the org.jboss.as.quickstarts.ha.singleton.service.primary-only service

See full server logs attached (note that the logs contain full QS testing following the QS readme).

This QS is not part of CD QS so it was not tested between 7.2.0.GA and 7.3.0.GA. However, I have tried to run it against CDx ZIP server and found out the warnings appear in CD17 and CD18. In CD16 there are no unexpected warnings. Was there any related change in CD17 server?