EF-Ext: Exception thrown when ConsurrentyToken is declared

System.Exception: An error occurred while updating the entries. See the inner exception for details. ---> System.Data.SqlClient.SqlException: The column 'Version' was specified multiple times for 'StagingTable'.
   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
   at System.Data.SqlClient.SqlDataReader.get_MetaData()
   at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
   at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
   at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
   at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet)
   at ..
(BulkOperation , SqlActionExecutor , SqlCommand , Int32 )
   at Z.BulkOperations.SqlActionExecutor.
(DbCommand , BulkOperation , Int32 )
   at Z.BulkOperations.SqlActionExecutor.(ExecuteAction , DbCommand )
   at Z.BulkOperations.DbActionExecutor.
(List`1 )
   at Z.BulkOperations.SqlProvider.
(List`1 )
   at ..
(BulkOperation )
   at Z.BulkOperations.BulkOperation.BulkUpdate()
   at Z.EntityFramework.Extensions.EntityBulkOperation`1.BulkUpdate()
   at Z.EntityFramework.Extensions.InternalBulkOperationManager.[
](BulkOperation`1 , DbContext , List`1 , Boolean , Type , String )
   at Z.EntityFramework.Extensions.InternalBulkOperationManager..
(SchemaEntityType )
   at System.Collections.Generic.List`1.ForEach(Action`1 action)
   at Z.EntityFramework.Extensions.InternalBulkOperationManager.[
](DbContext , BulkOperation`1 , IEnumerable`1 )
   at Z.EntityFramework.Extensions.InternalBulkOperationManager.[
](BulkOperation`1 , DbContext , IEnumerable`1 )
   at DbContextExtensions.BulkUpdate[T](DbContext this, IEnumerable`1 entities, Action`1 bulkOperationFactory)
   at Z.EntityFramework.Extensions.BulkSaveChanges.(DbContext , List`1 , Action`1 )
   at DbContextExtensions.BulkSaveChanges(DbContext this, Boolean useEntityFrameworkPropagation, Action`1 bulkOperationFactory)
   --- End of inner exception stack trace ---
   at DbContextExtensions.BulkSaveChanges(DbContext this, Boolean useEntityFrameworkPropagation, Action`1 bulkOperationFactory)
   at DbContextExtensions.BulkSaveChanges(DbContext this, Boolean useEntityFrameworkPropagation)