In superflat worlds, the mechanic of zombie piglins spawning when a nether portal is relit doesn't work.

When I was designing a new gold farm in 1.21.111 bedrock edition, I started designing it in a void superflat world, but then I noticed the zombie piglins weren’t spawning from the nether portals like usual. I went into a freshly generated normal world and the zombie piglins spawned from the portal.