Which parent creates this in Cattleya hybrids?

[Roberta]

The pink Rl. digbyana is subtly so... actually most digbyanas do have a bit of color, usually more on the backs of the segments. As for the frilly petals, that's the peloric form (fimbripetala) - form tends to be a bit wonky because of the heavy mid-rib. Here you can see some variation in my own Rl. digbyanas
Rl digbyana