@Rina8 Yes, this is normal. Reviews are not in chronological order. It doesn't have anything to do with discrimination- for instance, because my listing is in Mexico, a Mexican guest will see the reviews from my Mexican guests first. An American guest will see the reviews from your other American guests first.
Personally, I'd like them to be in chronological order, simply because you might have changed something about your listing since the most recent review showing (which may be from a year ago) may no longer reflect those changes. Like if a few guests mentioned the mattress wasn't comfortable, but you've since replaced it.