Error: 'System.owner' is not a persistable association

Hi guys

We are experiencing strange behaviour when trying to import an excel template as MxAdmin (configurator in excel import module; pretty standard).

com.mendix.modules.microflowengine.MicroflowException: com.mendix.systemwideinterfaces.MendixRuntimeException: com.mendix.core.CoreRuntimeException: Exception occurred in action '{"id":"[MendixIdentifier:: id=29836347531329537 objectType=System.User entityID=106]","type":"RetrieveIdAction"}', all database changes executed by this action were rolled back
	at ExcelImporter.ValidateTemplate (RetrieveFromCache : 'Get the language from the user')
	at ExcelImporter.IVK_SaveTemplate (SubMicroflow : 'Validate the template')

Advanced stacktrace:
	at com.mendix.modules.microflowengine.MicroflowUtil.processException(MicroflowUtil.java:143)

Caused by: com.mendix.core.CoreRuntimeException: com.mendix.systemwideinterfaces.MendixRuntimeException: com.mendix.core.CoreRuntimeException: Exception occurred in action '{"id":"[MendixIdentifier:: id=29836347531329537 objectType=System.User entityID=106]","type":"RetrieveIdAction"}', all database changes executed by this action were rolled back
	at com.mendix.core.actionmanagement.ActionManager.executeSync(ActionManager.java:176)

Caused by: com.mendix.systemwideinterfaces.MendixRuntimeException: com.mendix.core.CoreRuntimeException: Exception occurred in action '{"id":"[MendixIdentifier:: id=29836347531329537 objectType=System.User entityID=106]","type":"RetrieveIdAction"}', all database changes executed by this action were rolled back
	at com.mendix.util.classloading.Runner.doRunUsingClassLoaderOf(Runner.java:40)

Caused by: com.mendix.core.CoreRuntimeException: Exception occurred in action '{"id":"[MendixIdentifier:: id=29836347531329537 objectType=System.User entityID=106]","type":"RetrieveIdAction"}', all database changes executed by this action were rolled back
	at com.mendix.core.actionmanagement.CoreAction.processErrorState(CoreAction.java:303)

Caused by: com.mendix.connectionbus.ConnectionBusRuntimeException: An exception has occurred for the following request(s):
	IdentifierGetRequest:  Object types: [System.User]
	at com.mendix.connectionbus.RequestAnalyzer.doRequest(RequestAnalyzer.java:53)

Caused by: com.mendix.core.CoreRuntimeException: 'System.owner' is not a persistable association
	at com.mendix.connectionbus.DomainModelUtil$.getMetaAssociationOnChild(DomainModelUtil.scala:35)
	at com.mendix.connectionbus.DomainModelUtil.getMetaAssociationOnChild(DomainModelUtil.scala)
	at com.mendix.connectionbus.retrieve.ResultCreator.getMetaObjectAccessesWithoutConstraints(ResultCreator.java:513)
	at com.mendix.connectionbus.retrieve.ResultCreator.setSecurityOnDataRows(ResultCreator.java:419)
	at com.mendix.connectionbus.retrieve.ResultCreator.getResult(ResultCreator.java:77)
	at com.mendix.connectionbus.retrieve.DataStoreCaller.getResult(DataStoreCaller.java:82)
	at com.mendix.connectionbus.retrieve.GetRequestHandler.doRequest(GetRequestHandler.java:64)
	at com.mendix.connectionbus.RequestAnalyzer.doRequest(RequestAnalyzer.java:41)
	at com.mendix.connectionbus.ConnectionBusImpl.doRequest(ConnectionBusImpl.java:459)
	at com.mendix.core.action.user.Retriever$class.retrieveFromDatabase(Retriever.scala:32)
	at com.mendix.core.action.user.RetrieveIdAction.retrieveFromDatabase(RetrieveIdAction.scala:9)
	at com.mendix.core.action.user.RetrieveIdAction.retrieveFromDatabase(RetrieveIdAction.scala:32)
	at com.mendix.core.action.user.RetrieveIdAction.executeAction(RetrieveIdAction.scala:27)
	at com.mendix.core.action.user.RetrieveIdAction.executeAction(RetrieveIdAction.scala:9)
	at com.mendix.systemwideinterfaces.core.UserAction.execute(UserAction.java:49)
	at com.mendix.core.actionmanagement.CoreAction.doCall(CoreAction.java:260)
	at com.mendix.core.actionmanagement.CoreAction.call(CoreAction.java:248)
	at com.mendix.core.actionmanagement.CustomActionMonitorImpl$$anonfun$run$1.apply(CustomMonitoredAction.scala:14)
	at com.mendix.core.session.Worker$$anonfun$receive$3$$anonfun$2$$anon$1.execute(ActionDispatching.scala:144)
	at com.mendix.util.classloading.Runner.doRunUsingClassLoaderOf(Runner.java:36)
	at com.mendix.core.session.Worker$$anonfun$receive$3$$anonfun$2.apply(ActionDispatching.scala:146)
	at scala.util.Try$.apply(Try.scala:192)
	at com.mendix.core.session.Worker$$anonfun$receive$3.applyOrElse(ActionDispatching.scala:140)
	at akka.actor.Actor$class.aroundReceive(Actor.scala:465)
	at com.mendix.core.session.Worker.aroundReceive(ActionDispatching.scala:136)
	at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
	at akka.actor.ActorCell.invoke(ActorCell.scala:487)
	at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
	at akka.dispatch.Mailbox.run(Mailbox.scala:220)
	at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
	at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
	at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

Actually there were no remarkable security changes and the excel importer as latests updated version did his job very well. But we did include an excel export template manager module, after this the app worked also well. So when checking the last 10 commits I don't see any remarkable changes but the template manager and some object right changes (without any generalizations)...

Based on previous posts I checked whether there were some system.mebers with Non persistent entities in their generalization...but I could not find it.

So I am wondering whether one of you experienced similar behaviour with excel or outside the excel functionalities?

edit 1: replacing excel importer did not fix the issue

edit 2: when making a new admin user with a language setting, it works...So this is pretty strange to me...it feels like that Mendix "under water" mess with the access rights of the MxAdmin?