Query: include not applied on a subquery with navigation that is exposed by groupjoin's grouping

[maumar]

query:

(from l1 in l1s
                     join l2 in (from t in l1s
                                 where t.OneToOne_Required_PK1 != null
                                 select t.OneToOne_Required_PK1).Include(e => e.OneToOne_Required_PK2)
                     on (Nullable<int>)l1.Id equals l2.Level1_Optional_Id into grouping
                     orderby l1.Id
                     select new
                     {
                         l1,
                         grouping
                     })

we are unable to associate query source in the [grouping] with the query source that is stored in the Include query annotation.