Leganes inventory, #4: "otra imagen de Ntra Señora con el Niño en los brazos y dos angeles con la corona, de mano de Rubens, y su cerco de rosas y frutas de mano de Brueghel de vara de aldo y 3 qtas. de ancho, en 11.000." cited López Navió, “Analecta Calascanctiana” 1962, p. 269.

1666 inventory of the royal collection: en la pienza próxima a la galeria del Cierzo, médiodia del Alcázar, otra pintura con la imagen de Nuestra Señora y una guirnalda de flores de mano de Rubens, en trescientos ducados."

So -- it mattered to Leganes that Brueghel was a collaborator here; less so to whoever was doing the royal inventory.

My old notes on the painting say that the execution of Rubens's part is odd, a kind of cakey, painty overlay in somewhat yellow-white tones, not that bluey-pink smoothness that Rubens does in larger figures. It has more of the brushy vibrancy of Jan's parts of the painting, in fact.