I came back to my villager trading hall after a few hours of building to find all my villagers and named zombie in a minecart gone. The world never went into peaceful. It wasnt a zombie as that wouldnt have been able to cause a named villager to to despawn.

This world was created in 1.17 and has had no other issues.

This has greatly demotivated me as I don't want to spend hours getting new villagers just for them to be deleted, even while in minecarts. Issues like this always seem to ruin my bedrock edition worlds.