It was said the issue was fixed: http://forge.prestashop.com/browse/PSCSX-4266
But I have the problem in 188.8.131.52 (again?).
See attached table query.
It is interesting, that the remining product is in an older stock. It is shown as usable in Backend StockManager but we can not remove it (error:cannot remove 1 from 0).
Note, reference number and EAN are different, but id_product and id_product_attribute are equal. Therefore, PS should be able to remove them, right?