Over time, I noticed the same thing in various bags I had purchased from Natural Grocers. I used to just pick out the pink ones, worried they might have been contaminated with pink mold, but during the pandemic, when the store's stock was lower than usual, I didn't have any choice but to buy the bags with the pink-tinted quinoa--or to simply go without, which isn't much of an option for me, as I am on a very restricted diet as it is. So I asked the store buyer about it. He said he didn't know but he would ask the manufacturer. Eventually one day he had an answer for me. He said they splash a bit of pink dye in the flakes to mark each batch of their product. To be honest, at first I wasn't sure if I could believe it; for years I had been convinced it was actually a sign of spoilage. But I have allowed three unopened bags with the pink flakes to just sit on my shelf for perhaps several months now, and it doesn't look like the pink spots are spreading. So I figure that's a pretty good test of truth and that the pink quinoa, just like the rest of the batch, is safe to eat.