From Week's site and Google patent:  Parentage: Playboy x seedling derivative of Rosa soulieana

Mutabalis isnt listed as a parent anywhere.

From the Colonial District Rose Society:

"Flutterbye was introduced in 1999 and is classified as a yellow blend shrub. Tom Caruth, who has been very successful introducing many new roses, hybridized it. Flutterbye was a cross of Playboy with another rose that was from a cross of Sunsprite x Rosa soulieana derivative. The blooms have approximately 6 petals. It is an interesting rose bush as the colors of the blooms change color as they open and age. Initially the blooms are yellow with a yellow center or eye and yellow stamens. The blooms then change to yellow with a red edge, and some have a light orange shade to them. It is a very pretty bush in the garden, and it an excellent landscape rose. Our only problem was that it was a little winter tender and had to have more protection than Playboy. "

From the Memphis Rose Society: "Parentage: [Playboy X (R. Soulieana derivative X Sunsprite)] Hybridized by Tom CarruthIntroduced in 1996"