Logging controller: can't edit pre-existing logger

System.ArgumentNullException was unhandled by user code
Message=Value cannot be null.
Parameter name: id
Source=Unify.Framework.Logging.Engine.Interfaces
ParamName=id
StackTrace:
at Unify.Framework.Logging.CoreLogWriterEngineConfiguration..ctor(Guid id, String name, XElement configuration) in c:\Program Files (x86)\Jenkins\jobs\Framework Core (DEV)\workspace\Source\Logging\Unify.Framework.Logging.Engine.Interfaces\CoreLogWriterEngineConfiguration.cs:line 36
at Unify.Connect.Web.LogWriterAdapterDictionary.Transform(ILogWriterViewInformation sourceValue) in S:\hg\Product\IdentityBroker\v4.0\Source\Studio\Unify.Connect.Web\Models\Logging\Adapters\LogWriterAdapterDictionary.cs:line 60
at Unify.Connect.Web.LogWriterConfigurationViewInformationTwoWayAdapter.Transform(LogWriterConfigurationViewInformation sourceValue) in S:\hg\Product\IdentityBroker\v4.0\Source\Studio\Unify.Connect.Web\Models\Logging\LogWriterConfigurationViewInformationTwoWayAdapter.cs:line 87
at Unify.Connect.Web.LoggingController.CreateOrEditLogWriter(LogWriterConfigurationViewInformation configuration) in S:\hg\Product\IdentityBroker\v4.0\Source\Studio\Unify.Connect.Web\Controllers\LoggingController.cs:line 300
at lambda_method(Closure , ControllerBase , Object[] )
at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters)
at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.<>c_DisplayClass15.<InvokeActionMethodWithFilters>b_12()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
InnerException: