I was playing in a friend's realm and I left my dog ​​in the overworld, and when I entered the nether my dog ​​teleported and when I wanted to return to the overworld he took me out of the world and when I entered the realm, I kind of returned to the place where I saved my game, It also happened with a horse that I tamed and I'm not sure if it's just the tamed mobs or in general

 Pots: I don't know if this bug affects normal worlds