I had it happen at y 253 above the nether roof, zombies spawned on netherack which I had placed. Left and joined server, unloaded and reloaded the server, still happened. Since i was on hard mode when one got on low health loads more spawned. Two things I should also mention I was building a shared aggresion zombie piglin farm when it started happening and i was using an Aternos server. Only mods on were do a barrel roll(elytra movement) and sodium, both client-side. I hope it gets patched since I've had 5 of them spawn at once and that results in an average efficiency drop of 7% in the gold farm(since it lowers the mob cap for zombie piglins to fill by 7%). No spiders and creepers though
Number_Fan
I had it happen at y 253 above the nether roof, zombies spawned on netherack which I had placed. Left and joined server, unloaded and reloaded the server, still happened. Since i was on hard mode when one got on low health loads more spawned. Two things I should also mention I was building a shared aggresion zombie piglin farm when it started happening and i was using an Aternos server. Only mods on were do a barrel roll(elytra movement) and sodium, both client-side. I hope it gets patched since I've had 5 of them spawn at once and that results in an average efficiency drop of 7% in the gold farm(since it lowers the mob cap for zombie piglins to fill by 7%). No spiders and creepers though