An item with the same key has been added

I upgraded to IdB 5.2.1 in Dev and the Aurion Person connector has stopped working with the error below. It has disabled itself and won't let me re-enable it, so I can't run the import again, or even clear the connector.

The key is the Aurion WAMIKey and there cannot be a duplicate. The Aurion DB in dev has not been updated since it was working with Idb 5.1 (no new persons added).

Message    An error has occurred: An item with the same key has already been added.
Type    System.ArgumentException
Stacktrace    at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at Unify.Connectors.Aurion.AurionConnectorInformationFactoryBase`1.Transform(XElement sourceValue)
at Unify.Product.IdentityBroker.ConnectorControllerBase.GetSpecializedConnector[TInfo,TExtended](Guid connectorId, String expectedType, String callingPath, Func`2 toExtended)
at Unify.Product.IdentityBroker.PluggedConnectorControllerBase`2.GetConnector(Guid connectorId)
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<getexecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)
--- 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 System.Web.Http.Controllers.ApiControllerActionInvoker.<invokeactionasynccore>d__0.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 System.Web.Http.Controllers.ActionFilterResult.<executeasync>d__2.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 System.Web.Http.Filters.AuthorizationFilterAttribute.<executeauthorizationfilterasynccore>d__2.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 System.Web.Http.Dispatcher.HttpControllerDispatcher.<sendasync>d__1.MoveNext()
</sendasync></executeauthorizationfilterasynccore></executeasync></invokeactionasynccore></getexecutor>