dave weil writes:

Maybe this isn't all that unusual, but today I noticed a couple of
scattered pure white blooms amongst the pink.

Dave,
Last year one of my Mons. Tillier's did the same thing all season. I got pale
apricot/yellows and some half 'n half, along with regular blooms. I could
never isolate a cane where the pale color was stable. It would move from cane
to cane.
Not to suggest this will happen to The Fairy, but Mons. T cankered badly this
spring, so much so that I finally removed him. I tried to get some cuttings
rooted before the shovel found him, but none of them survived.
Julie