NHibernate.QueryException: could not resolve property:

I've got a bit of code thats throwing NHibernate.QueryException: could not resolve property: Exception. Orders have one to many Jobs. And the following code trying to find orders with jobs matching certain criteria.

    var criteria = Session.CreateCriteria(typeof(IOrder), "o");
    criteria.CreateAlias("o.Customer", "c");
    //… add some restrictions on orders

    var jobCriteria = DetachedCriteria.For(typeof(IJob), "j");
     // add some restrictionson Jobs 
    jobCriteria.Add(Eq(.....
    jobCriteria.Add(Eq(.....
    jobCriteria.Add(Eq(.....
    // then just get the order id from jobs as we just display the orders in the results
    jobCriteria.SetProjection(Projections.Alias(Projections.Property("Order"), "o1"));
    jobCriteria.Add(EqProperty("Order.Id", "o.Id")); // <-------

    criteria.Add(Subqueries.Exists(jobCriteria));

throws exception

    NHibernate.QueryException: could not resolve property: o of: lep.job.IJob
      at NHibernate.Persister.Entity.AbstractPropertyMapping.ToType
      at NHibernate.Persister.Entity.AbstractEntityPersister.GetSubclassPropertyTableNumber
      at NHibernate.Persister.Entity.BasicEntityPropertyMapping.ToColumns
      at NHibernate.Loader.Criteria.CriteriaQueryTranslator.GetColumnsUsingProjection
      at NHibernate.Persister.Entity.AbstractPropertyMapping.ToType
      at NHibernate.Persister.Entity.AbstractEntityPersister.GetSubclassPropertyTableNumber
      at NHibernate.Persister.Entity.BasicEntityPropertyMapping.ToColumns
      at NHibernate.Loader.Criteria.CriteriaQueryTranslator.GetColumnsUsingProjection

How can I say "o.Id" from parent criteria, ie the Order.Id must match the job's order Id that got matched in Subqueries.Exists???

NHibernate version 5.2.5