I can confirm this bug, it just happened on my multiplayer server. Travelling through a portal in the nether at 5, 8, -127 set me on fire when I arrived in the overworld at 40, 64, -1000. The was no lava near the overworld portal, but going to the nether coordinates of the portal in the overworld (5, 8, -127) and removing the lava there stopped me from being set on fire when using the portal.
Can confirm this is still present on 1.20. I cannot count how many times I see TWO ghasts spawn directly in front of me. I kill those, and two more will spawn in less than a minute. And you can absolutely forget about traversing a soul sand valley. I must have killed 75 skeletons on my way across it. Kill three or four and watch them respawn in less than 10 seconds. It's impossible to climb scaffolding or anything else because you're in the middle of a shooting gallery. Other biomes are just as bad with constant piglin and magma cube spawns. It's just ridiculous. This can't be hard to turn down can it? Just put some more gaps between spawns, and maybe only spawn one ghast at a time.