That's intentional lol, I can't imagine the biology to that either
Mostly intentional, since they're supposed to be hybrids lol
I also think artist dont know how to handle the ears, bc they want to add animal ears but don't know how to get rid of the humans ones since most of them don't ALWAYS have the animal characteristics and only show sometimes and stuff
There are a few stories here where they did think it through tho so they don't have 4 ears
Ever since I noticed that I've tried to stop reading animal characteristic stories. It's just funny
I think authors just want it to be cute, like when you put on animal ears headband, and they didn't bother to make sure anatomy matched. But also, it just looks weird for a human face to not have ears by the side, so some authors who are creative will put the animal ears in similar position as the human ear instead of the top of the head. Others hide the sides with hair if the ears are on top. Either way, the 4 eared ones are funny looking.
In many mangas or webtoons, the characters which have the animal traits (such as wolf, puppy, kitty etc) have both human ears and animal ears... it's like they have total 4 ears. Is that intentional or the artists forgot to notice