I was playing in a world where I had ~180 villagers and another 30 mobs. I entered the nether and saw a few bees came in, I tried to get them back into the over world, and after failing I used /tp @e @s. I had never changed ticking area and it said every one of the mobs in the over world also teleported, but I saw none of them. When I came back every mob was gone. It wasn't that they died in the nether because I didn't see them, I wasn't that they wandered of because i was only gone for 30 mins. it wasn't that they despawned because I gave one a name tag, and traded with a lot of them. My only guess is that they traveled to the cords in the over world that were the same as mine in the nether. My only portal was blocked of in the village they were in. I never exited the world between when I last saw them and when I saw them gone

I was in survival peaceful, don't judge how I spend my time