That was the same with my plant previous bloom (previous winter) when I bought it in bloom. Sounds like you have the same plant.
This year every bloom has the pink blush... just inspected my plant in high light, and guess what
The oldest blooms, now at least 7 weeks on the plant, don't have the pink blush anymore, also the green in the center has faded, hardly visible. It still has some pink showing on the petals/sepals, which is more prominent in the blooms that opened later. Last year it had some pink on the petals/sepals too but not as clearly as this year, however I didn't spot it on the first blooms that opened, when they opened. Seems that for my plant the blooms become more evenly white when they age.
Nicole