Another issue I encountered is not yet identified at MOS, not in the context I encountered it. The error was written to the logs every minute:
<Error> <oracle.wsm.resources.policymanager> <WSM-02084> <Access denied. Permission "oracle.wsm.security.PolicyManagerPermission" is required to access the wsm policy manager "UsageTracker" method "recordUsage".>
The only MOS reports on this was partially applicable for my situation: Bug 23279489 : WSM-02084 ERROR WHILE STARTING WSM/SOA SERVER IN DOMAIN PARTITION SETUP
The SOA Suite Domain was setup using a separate SOA and separate WSM Cluster, however the MOS note speaks about a created partition to be deleted... however domain partition is not yet supported for SOA 12.2.1 so that surprised me.
So here's what brought me the solution.
Login to Fusion Middleware Control, expand the hamburger menu and right click on the domain, select Security and the Application Policies
Select the ws-pm application stripe and edit the policy for policy.Acessor
4. Click on Add and search for the resource UsageTracker and method record Usage, click continue
5. Grant Invoke and All permission
6. After done click ok and restart your domain.
Afterwards, the errors in the AdminServer and OWSM managed server logs are dissapeared.