trace

15:46:25,701 ERROR ~ an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session)
org.hibernate.AssertionFailure: collection owner not associated with session: models.Order.cartItems
	at org.hibernate.engine.Collections.processDereferencedCollection(Collections.java:110)
	at org.hibernate.engine.Collections.processUnreachableCollection(Collections.java:62)
	at org.hibernate.event.def.AbstractFlushingEventListener.flushCollections(AbstractFlushingEventListener.java:262)
	at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:100)
	at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
	at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)
	at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383)
	at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133)
	at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:76)
	at play.db.jpa.JPAPlugin.closeTx(JPAPlugin.java:379)
	at play.db.jpa.JPAPlugin.afterInvocation(JPAPlugin.java:323)
	at play.plugins.PluginCollection.afterInvocation(PluginCollection.java:434)
	at play.Invoker$Invocation.after(Invoker.java:225)
	at play.Invoker$Invocation.run(Invoker.java:279)
	at play.server.PlayHandler$NettyInvocation.run(PlayHandler.java:235)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:207)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)
15:46:25,884 ERROR ~

@69ib5njk3
Internal Server Error (500) for request DELETE /admin/users/2?x-http-method-override=DELETE

JPA error
A JPA error occurred (Cannot commit): collection owner not associated with session: models.Order.cartItems

play.exceptions.JPAException: Cannot commit
	at play.db.jpa.JPAPlugin.closeTx(JPAPlugin.java:392)
	at play.db.jpa.JPAPlugin.afterInvocation(JPAPlugin.java:323)
	at play.plugins.PluginCollection.afterInvocation(PluginCollection.java:434)
	at play.Invoker$Invocation.after(Invoker.java:225)
	at play.Invoker$Invocation.run(Invoker.java:279)
	at Invocation.HTTP Request(Play!)
Caused by: org.hibernate.AssertionFailure: collection owner not associated with session: models.Order.cartItems
	at org.hibernate.engine.Collections.processDereferencedCollection(Collections.java:110)
	at org.hibernate.engine.Collections.processUnreachableCollection(Collections.java:62)
	at org.hibernate.event.def.AbstractFlushingEventListener.flushCollections(AbstractFlushingEventListener.java:262)
	at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:100)
	at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
	at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)
	at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383)
	at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133)
	at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:76)
	at play.db.jpa.JPAPlugin.closeTx(JPAPlugin.java:379)
	... 5 more