I tasted some famous-brand Greek yogurt that was about 1 or 2 weeks past the best-by date recently. The taste was flawless, but there was something very weird

I tasted some famous-brand Greek yogurt that was about 1 or 2 weeks past the best-by date recently. The taste was flawless, but there was something very weird about the texture, like it was subtly sandy or something. I ended up throwing several cups away. I only recently replaced my half empty "Best-by Nov 2016" Costco Saigon Cinnamon with a brand new bottle of the same. The new bottle tastes a little stronger but I sort of regret throwing the old bottle away since I don't think it will actually matter.