Hi Frank,

Peace lilies with white blooms, like mine, can turn green before fading away. Some plants will have green flowers right off the bat.
It happens from time to time, from one plant to another and nothing to be concerned about.I think the green ones are kinda nice!

Billy Rae

I find that PL in low light will not get a white bloom. Try giving it a bit more light and see if that helps it.

It could be the light. But then again, mine are in full, deep shade and the blooms are all white. Although, since they're outside, they still get natural light, even though they don't get direct sunlight.

If you look at the new flowers, they are smaller and the new growth looks a bit bleached and thin, this also suggests low light.