I realized I've been eating Hetbahn that expired two months ago

‌I used to only eat plain white rice, so I decided to try buying some multigrain rice.
But when it came to mealtime, I just didn't feel like eating it and kept sticking to the white rice.
I recently started eating the multigrain rice, only to realize that the expiration date had passed by two months.
I had no idea while eating it. Usually, if rice goes bad for even a single day, it smells sour,
but is it possible for instant rice to be like this?