RowCount not working with JoinEntityAlias

[adigourdi]

When using JoinEntityAlias with queryOver.RowCount() or queryOver.ToRowCountQuery() throws an error

Exception thrown: 'NHibernate.QueryException' in NHibernate.dll
An exception of type 'NHibernate.QueryException' occurred in NHibernate.dll but was not handled in user code
could not resolve property: child2 of: Namespace.To.Child1

Example

Let's say I have 3 classes Parent, Child1, and Child2.
Both childs have a property Parent referencing Parent class
And I'd like to join between Child1 and Child2 using the parent property

Child1 child1 = null;
Child2 child2 = null;

var query = session
    .QueryOver(() => child1)
    .JoinEntityAlias(
        () => child2,
        () => child2.Parent.Id == child1.Parent.Id,
        NHibernate.SqlCommand.JoinType.InnerJoin
    )
    ;

// [ ... ] // ommitted code for brevity

query // pagination
    .Skip(20)
    .take(10)
    ;

query.List(); // returns the correct list paginated
query.RowCount(); // throws the error above
query.ToRowCountQuery().SingleOrDefault<int>(); // throws the same error

Notes

1. I'm using Future for this, the same issue occurs
2. both RowCount() and ToRowCountQuery() work fine with JoinAlias
3. I haven't tested JoinEntityQueryOver(), but I believe the same issue applies

[adigourdi]

After attempting a workaround, I found the issue is caused by the queryOver.Clone() method

I tried cleaning the select fields, retrieve only the ID, and counting the result list

var queryNonPaginated = query.Clone()
    .SelectList(sel => sel.Select(c => c.Id)) // with or without this line
    ;
total = queryNonPaginated.List().Count; // throws same error in OP

Using the original query object works as expected

total = query.List().Count; // int value