Null key on Adapter import with changed key.

Adapter request to update entity to adapter space failed.
Adapter request to update entity e118589e-def1-4f63-9ae6-0b9285e016e8 to adapter space 777fb0b6-f864-46e3-8f03-a1dbf8dd1427 failed with reason The entity key of the entity with id e118589e-def1-4f63-9ae6-0b9285e016e8 contains a null value. For reference this key appears as the following '<null>'. Ensure that the attribute corresponding to this key value has been configured correctly in the respective identity management product... Duration: 00:00:00.0312500
Error details:
Unify.Framework.UnifyEngineException: The entity key of the entity with id e118589e-def1-4f63-9ae6-0b9285e016e8 contains a null value. For reference this key appears as the following '<null>'. Ensure that the attribute corresponding to this key value has been configured correctly in the respective identity management product..
at Unify.Product.IdentityBroker.Adapter.<>c__DisplayClassb1.<CheckAnchorChangeOnSave>b__a9(KeyValuePair`2 keyValue)
at Unify.Framework.Visitor.<>c__DisplayClass1`1.<Visit>b__0(T item, Int32 index)
at Unify.Framework.Visitor.Visit[T](IEnumerable`1 visitCollection, Action`2 visitor)
at Unify.Framework.Visitor.Visit[T](IEnumerable`1 visitCollection, Action`1 visitor)
at Unify.Product.IdentityBroker.Adapter.CheckAnchorChangeOnSave(IEntitySchema connectorSchema, IEnumerable`1 entitiesToSave, IEntityPartitionUpdatableContext connectorContext, IEnumerable`1 entityIds)
at Unify.Product.IdentityBroker.Adapter.UpdateEntities(IEnumerable`1 entities, Boolean reflect)
at Unify.Product.IdentityBroker.Adapter.UpdateEntity(IAdapterEntity entity, Boolean reflect)
at Unify.Product.IdentityBroker.Adapter.UpdateEntity(IAdapterEntity entity)
at Unify.Product.IdentityBroker.AdapterNotifierDecoratorBase`1.UpdateEntity(IAdapterEntity entityToSave)
at Unify.Product.IdentityBroker.LDIFAdapterBase.ExportChanges(ExportedLDIFForAdapter exportedLdifForAdapter)
at Unify.Product.IdentityBroker.LDIFAdapterServiceHostDecoratorBase.ExportChanges(ExportedLDIFForAdapter exportedLdifForAdapter)
at SyncInvokeExportChanges(Object , Object[] , Object[] )
at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)