vanishing villagers

So I am playing on a friends realm and i created my own village by curing villagers but whats been happening is that when i log on day after day i notice they just vanish i started with 20 fully name tagged with lots of space in their houses so they wouldnt glitch through anything and today i came on and now theres only 3 left. im not surer if it is someone greifing me but this has been happening the past month at all the villages i try to establish. Has anyone else reported this bug