Arel from git seems to have broken "except"

I was playing with the latest arel, rails and squeel, and I tried a simple thing :

Facture.joins(:devise).sum("montant_ttc / taux")

which used to work, but now does :

SELECT SUM(montant_ttc / taux) AS sum_id FROM "facture" INNER JOIN "devise" ON "devise"."id_devise" = "facture"."id_devise" ORDER BY numero

The query is perfect, only the last part, ORDER BY numero, which comes from a default_scope, should not be there. I tried adding an except(:order) but it seems a noop right now...