Entity framework AddOrUpdate key violation

I am using a method AddOrUpdate

from EntityFramework 6.0

which doc should execute:

AddOrUpdate (IDbSet, TEntity [])
Adds or updates objects by key when SaveChanges is called. Equivalent to the "upsert" operation from the database. This method can be useful when seeding data using migration.

I want to do a "bulk upsert", I have a trigger that nightly transfers data from another server and inserts new values ​​and existing updates. The code I'm using:

    private void InsertConfigurations(IEnumerable<Configuration> configs)
    {
        using (var context = new MyEntities())
        {
            using (var scope = new TransactionScope(TransactionScopeOption.Suppress))
            {
                    context.Configuration.AutoDetectChangesEnabled = false;
                    context.Configurations.AddOrUpdate(configs.ToArray());
                    context.SaveChanges();
                    scope.Complete();
            }

        }
    }

      

        
        
        
      

    

Now this code fails every time:

System.Data.Entity.Infrastructure.DbUpdateException: An error occurred while updating records. See Inner Exception for details. ---> System.Data.Entity.Core.UpdateException: An error occurred while updating records. See Inner Exception for details. ---> System.Data.SqlClient.SqlException: Violation of PRIMARY KEY constraint "PK_Configuration_ID". Unable to insert duplicate key into 'dbo.Configuration' object. The duplicate key value is (218383).

From what I understand from UPSERT

, shouldn't there be a key reason to use it to avoid the exact problem I am facing? Am I doing something wrong?

StackTrace:

   --- End of inner exception stack trace ---
   at System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update()
   at System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.<Update>b__2(UpdateTranslator ut)
   at System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update[T](T noChangesResult, Func`2 updateFunction)
   at System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update()
   at System.Data.Entity.Core.Objects.ObjectContext.<SaveChangesToStore>b__35()
   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
   at System.Data.Entity.Core.Objects.ObjectContext.SaveChangesToStore(SaveOptions options, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction)
   at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass2a.<SaveChangesInternal>b__27()
   at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)
   at System.Data.Entity.Core.Objects.ObjectContext.SaveChangesInternal(SaveOptions options, Boolean executeInExistingTransaction)
   at System.Data.Entity.Core.Objects.ObjectContext.SaveChanges(SaveOptions options)
   at System.Data.Entity.Internal.InternalContext.SaveChanges()
   --- End of inner exception stack trace ---
   at System.Data.Entity.Internal.InternalContext.SaveChanges()
   at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
   at System.Data.Entity.DbContext.SaveChanges()
   at D.DataService.DataService.InsertConfigurations(IEnumerable`1 configs) in c:\localdev\DWeb\DWeb\D.DataService\DataService.cs:line 41
   at D.DataService.DataService.UpdateAllConfigurations() in c:\localdev\DWeb\DWeb\D.DataService\DataService.cs:line 27
   at D.DataService.Job.ConfigurationUpdaterJob.Execute(IJobExecutionContext context) in c:\localdev\DWeb\DWeb\D.DataService\Job\ConfigurationUpdaterJob.cs:line 14