Object Browser: Editing objects via multiselect runs into an error (4379475)

ERROR (VI.FormBase.ExceptionMgr  ) : Entity is no interactive proxy.

Full error:

ERROR (VI.FormBase.ExceptionMgr  ) : Entity is no interactive proxy. System.ArgumentException: Entity is no interactive proxy.
   at QBM.AppServer.Client.ServiceUnitOfWork.<GenerateAsync>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at VI.Base.SyncActions.Do[T1,T2,T3,T4](T1 p1, T2 p2, T3 p3, T4 p4, Func`5 action)
   at VI.DB.Sync.SyncUnitOfWorkExtensions.Generate(IUnitOfWork unitOfWork, IEntity entity, String eventname, IDictionary`2 parameters)
   at VI.ObjectBrowser.Parts.GenerateForm.btnGenerate_Click(Object sender, EventArgs e)    at QBM.AppServer.Client.ServiceUnitOfWork.<GenerateAsync>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at VI.Base.SyncActions.Do[T1,T2,T3,T4](T1 p1, T2 p2, T3 p3, T4 p4, Func`5 action)
   at VI.DB.Sync.SyncUnitOfWorkExtensions.Generate(IUnitOfWork unitOfWork, IEntity entity, String eventname, IDictionary`2 parameters)
   at VI.ObjectBrowser.Parts.GenerateForm.btnGenerate_Click(Object sender, EventArgs e)