Same. I've noticed a few times where a solid strand of my hair suddenly turned into a curious grey/white colour, with perhaps a bit of a reddish interval inbetw

Same. I've noticed a few times where a solid strand of my hair suddenly turned into a curious grey/white colour, with perhaps a bit of a reddish interval inbetween, then after some length turns back into the original colour... And once it didn't turn all the way, but it got stuck on a curious reddish-yellow colour, then reverted.