I have the following exception and related WARN each time I activate a website node.
Default installation, no changes to workflow etc..

This happens always:
IWARN info.magnolia.context.AbstractRepositoryStrategy AbstractRepositoryStrategy.java(release:153) 19.08.2008 17:25:58 session has been already closed website
WARN info.magnolia.context.AbstractRepositoryStrategy AbstractRepositoryStrategy.java(release:153) 19.08.2008 17:25:58 session has been already closed website

and this randomly:
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WARN info.magnolia.module.workflow.jcr.JCRExpressionStore JCRExpressionStore.java(getHierarchyManager:293) 19.08.2008 17:25:45 The workflow expression session has pending changes. Will clean the session
java.lang.Exception
at info.magnolia.module.workflow.jcr.JCRExpressionStore.getHierarchyManager(JCRExpressionStore.java:293)
at info.magnolia.module.workflow.jcr.JCRExpressionStore.storeExpression(JCRExpressionStore.java:105)
at openwfe.org.engine.impl.expool.AbstractExpressionStore.loadEngineEnvironment(AbstractExpressionStore.java:136)
at openwfe.org.engine.impl.expool.SimpleExpressionPool.fetchEngineEnvironment(SimpleExpressionPool.java:406)
at openwfe.org.engine.impl.expool.CachedExpressionPool.fetchEngineEnvironment(CachedExpressionPool.java:232)
at openwfe.org.engine.impl.expool.SimpleExpressionPool.reschedule(SimpleExpressionPool.java:1330)
at openwfe.org.engine.impl.expool.SimpleExpressionPool.trigger(SimpleExpressionPool.java:1393)
at openwfe.org.time.Scheduler$Entry.trigger(Scheduler.java:490)
at openwfe.org.time.Scheduler.wakeup(Scheduler.java:461)
at openwfe.org.time.Scheduler$SchedulerThread.run(Scheduler.java:577)