Iron golems spawn then despawn when there aren't enough villagers

Hey there! 

I'm just enjoying a survival world but noticed something that could be a bug (and made me sad because I lost a bunch of iron 😆).

Despite the cap on the amount of iron golems per villager, the game allowed me to make heaps, and then within 30 seconds or so they just despawned.

This could be a problem for other uses when they are losing iron 😊

Thanks,

Microsoft - UnarmedBulb5206, PS4 - WeatherBore2086