My villager without the name tag despawning

My village used to have like 20+ villager because i breed them a lot. Some of them i make a professional to trade with and put a name tag so he not gonna despawn. But the other villager that don’t have a name tag they all despawn they all just disappear. I’m in peaceful mode so no mob can kill them for sure and i lock them up in the room so they can’t leave but they just disappear. Please fix . I’m tired of breeding them