Structures disappear when you get close after they first render in

Playing on my server I've discovered that new structures (in unexplored areas / unsaved chunks) initially render in but then vanish when I approach them. It's like the game shows me what should be there whilst it loads it in properly, but then decides that it won't generate them after-all.

I've not tested all structures, but it has affected all villages, ruined portals, woodland mansions, pillager towers, and end cities I've tried it on.

I have downloaded a backup of the world to test it running on my device instead of the server and it doesn't happen when running directly in Minecraft on my device.

I've also tried on the server with a fresh world that has the same seed in case it was my specific world misbehaving, and I've tried another seed with a village and a woodland mansion next to spawn.

Whenever testing on the server the structures vanish when I get close after they initially appear.