Jeff and Michelle are two villagers in my manually built village. I have them locked in a glass room in order to grow the village. They had a child and it was about 15 minutes old when it disappeared. The Minecraft wiki states that a villager cannot de-spawn, and that it can only forget about its village after leaving its boundary for 6 seconds. I am on peaceful difficulty, all three of the villagers were in a sealed room, I left to work on the Village and I returned to find the their child had disappeared.
This is the room I had locked the family inside. It has more than enough beds and two job site blocks (lecterns). Both of the villagers are named via nametag (Jeff and Michelle), because it was the easiest way to catch a zombie villager without it despawning. I have read up on this and most sources say that this shouldn't matter. So what happened to the child? I highly doubt it suffocated or teleported outside, as there is lots of free space around the beds. And its on peaceful so there is no way they could have died to a zombie. Do villagers die due to starvation or does that just affect willingness like I've read? How do I prevent this from happening again and what are the possible reasons it happened?