Around 11:10 AM this morning, a bundle push was triggered for a role change. This has left the Splunk search heads in a state where they are not able to sync with each other.
The impact of this is limited to search head replication functionality, such as modifying alerts/saved searches being replicated to other search heads. Data ingest and search itself is unaffected.
We have opened a P1 ticket with Splunk, and are working on testing resolutions in our nonproduction environment.