villagers despawn

Hello there. I play on Minecraft for the Nintendo Switch, and I have little villager apartments right next to my house to trade with. The only problem being that they keep poofing out of existence. Their homes are fenced off and well lit, and I even used nametags on them so they won't despawn. However, they will disapear anyway. They'll disappear when I'm far away when the chunk isn't loaded, when I'm logged off, one time I was in the village, passed one, did business with another villager, went back to trade with the first guy and he was just gone. Even stranger still, every now and again, they'll return. I had a level 2 post-zombified farmer who accepted carrots, he disapeared, but like 3 weeks later he was just back after his position was available because the replacement farmers disappeared. I'm really getting tired of this, I just want my villagers to stay