Unexpected grouping for SELECT queries on views that include a GROUP BY

I've a set of models like the one that I've already explained in https://issues.jboss.org/browse/TEIID-1562. In addition I've a physical model, named sole_rugiada_phy, which extracts data from a SQL Server 2005 database. On top of it there's a view model, named sole_rugiada_log, which transform some fields and does some joins grouping.

In particular the base table named 'vendita_referenza' is defined as follows:

SELECT
		SR_op.codop, CAST(SR_v.n_bolla AS VARCHAR) AS codice, SUP_ro.codref, SR_v.data, CAST(SR_v.n_prog AS INTEGER) AS n_prog, CAST(SUM(SR_v.quantita) AS INTEGER) AS quantita, SUM((((SUP_r.quantita / SUP_ro.quantita_reale) * SR_v.quantita) * SR_v.prezzo)) AS fatturato, COUNT(*) AS groupdim
	FROM
		((sole_rugiada_phy.MISURA124.dbo.VENDITA_REFERENZA AS SR_v INNER JOIN support_log.mediator.referenza_op AS SUP_ro ON RTRIM(LTRIM(CAST(SR_v.codref AS VARCHAR))) = SUP_ro.codice) INNER JOIN support_log.mediator.referenza AS SUP_r ON SUP_ro.codref = SUP_r.codref) INNER JOIN sole_rugiada_log.misura124.solerugiada.op AS SR_op ON SUP_ro.codop = SR_op.codop
	WHERE
		SR_v.data >= PARSEDATE('20090701', 'yyyyMMdd')
	GROUP BY SR_op.codop, SR_v.data, SR_v.n_bolla, SR_v.n_prog, SUP_ro.codref

If I run the following query, that is a simple SELECT statement, everything works fine:

SELECT
    codop,
    codice,
    codref,
    data,
    n_prog,
    quantita,
    fatturato,
    groupdim
FROM
    sole_rugiada_log.misura124.solerugiada.vendita_referenza

The query above retrieves 18717 records. But if I remove some fields from the SELECT statements something goes wrong. Take for example the following query:

SELECT
    codop,
    codref,
    data,
    quantita,
    fatturato
FROM
    sole_rugiada_log.misura124.solerugiada.vendita_referenza

The above query gets only one record, which is a grouping over all the record, even if it doesn't include a GROUP BY clause. It's not clear what type of aggregation it does. It seems to be a sum of all records, but the result is not totally exact. The value of 'fatturato' is near the real sum (5043502.561000000 instead of 5046687.249000000), but the value of 'quantita' is much different from the real sum (489566 instead of 5537638).

I noticed that removing the GROUP BY from the definition of the base table the problem disappears, but, of course, most of times this cannot be used as a workaround.

Attached there are the project of the VDB and a log of the execution of the query that produces the wrong result.