Azure data sync troubleshooting upload failures

Question

In the Azure data sync logs every sync I get a warning message that claims that 4 upload records have failed. However there is no detail associated with the log record, so I have no idea what table these 4 records are missing from or what the PK is of the records that is causing the problem.

Is there a way to troubleshoot this issue? Perhaps by querying the tables data sync adds to the hub/member databases?

In the event log in the on premise server, I'm seeing a stream of events similar to this:

id:SyncServiceTask_ExceptionProcessingRequest, rId:, sId:b375b9d2-4596-4a69-9b87-71dc351108bc, taskId:e63d1aa8-1bf6-4bd5-b877-94b623004f89, e:'Type=System.ServiceModel.FaultException1[[Microsoft.SqlAzureDataSync.ClientServerCommon.DssFaultException, Microsoft.SqlAzureDataSync.ClientServerCommon, Version=4.3.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]],Message=Object reference not set to an instance of an object. ,Source=Microsoft.SqlAzureDataSync.SyncAgentServiceApi,StackTrace=
at Microsoft.SqlAzureDataSync.SyncAgentServiceApi.SyncAgentServiceApi.CompleteDataSyncTask(String responseXml, Guid taskId, Guid tracingId) at Microsoft.SqlAzureDataSync.SyncControllerLib.SyncControllerTaskBase.CompleteTask(Guid taskId, BaseResponse response),', eType:'Type=System.ServiceModel.FaultException1[[Microsoft.SqlAzureDataSync.ClientServerCommon.DssFaultException, Microsoft.SqlAzureDataSync.ClientServerCommon, Version=4.3.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]', eMessage:'Message=Object reference not set to an instance of an object. ', eTypeInner:, eMessageInner: