DbUpdateException on DbContext in Autofac

Question

I have a EF DbContext which I registered in my Autofac container:

builder.RegisterType<Data.Foobar>().As<IFoobarContext>().InstancePerDependency();

This object is being used in other objects which I also registered in my Autofac container:

builder.RegisterType<InteractionManager>().As<IInteractionManager>().SingleInstance();

Now I'm getting a error once in a while after updating the database:

Exception: System.Data.SqlClient.SqlException Message: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_ParticipantCode_Participant". The conflict occurred in database "database", table "dbo.Participant", column 'Id'. The statement has been terminated.

After a IIS reset this error vanishes and the same action will run without any exceptions. I know for sure that the FK is correct.

After some research it looked like the dbcontext could be in an inconsistent state. I added the following to my Data.Foobar registration:

builder.RegisterType<Data.Foobar>().As<IFoobarContext>().OnActivating(x =>
    {
         x.Instance.Dispose();
         x.ReplaceInstance(new Data.Foobar());
    })
    .InstancePerDependency();

This does not work either.

It is a really strange issue with not much to go on so that is why I am asking all of you. Could it be that because my InteractionManager is a singleinstance, my dbcontext is also and the database state is not being updated correctly?