I haven't been on since June, but I noticed it for the last 1-2 years or so. Especially on the smaller subs where any given comment would only get a handful of upvotes. Someone would write a long helpful explanation, I upvote, and nothing happens. The score would stay at 1 or whatever.
It's not like I was spamming votes either. I would make a point of only voting on one comment per post so my vote would count. But it was still usually 50/50. Vote fuzzing was there for years, but this was different. The comments that were less popular seemed to be affected the most.
Nepal? That would be my guess because of the colorful flags. The river must make quite a sound when it's like that.