Mobs spawn at a much higher than normal rate in Nether fortresses, especially in soul sand valleys

No, this is just how the mob spawning algorithm works. If anything is to be considered a bug, it should be that there are not enough mobs spawning outside the Fortress which causes this imbalance. Also, the comment about wither skeleton spawning supposed to be much less than blazes is simply incorrect since wither skeletons have a spawn chance of 8/28 (out of every 28 mobs that spawn in a Fortress about 8 should be wither skeletons) while blazes have a spawn chance of 10/28.

Might be a soul sand valley specific issue since my nether fortress in a nether waste biome (and a portion spread into a crimson forest) barely spawns any wither skeletons or natural blazes.

Even if it isn't a bug, something needs to be changed with the spawns because fortresses in soul sand valleys aren't even approachable.

Can someone confirm please if it is in Pre-Release 4? Thanks!

Yes, still occur in pre4

Can confirm, still happens

Those new images are after I did /kill on all the nearby mobs multiple times

Even though skeleton spawning was fixed, this still happens. I have actually seen this glitch happen with fortresses in soul sand valleys, basalt deltas, crimson forests, warped forests, and sometimes even nether wastes (if other biomes are nearby).

Confirmed in 1.16 Pre-release 8.

ongoing with ghasts and skeletons

I sincerely hope this is a bug bc we were not even by a fortress but a soul sand area n hubby n i had to stop playing, even though we started a new game for the nether update but its Unplayable in its current condition.  There were at least 50 skeletons n they n the ghast immediately re-spawned after death and esp on soul sand.... its pointless and aggravating to even try...i really hope it gets fixed,  bug or not. Thanks! 

Can I have ownership of this ticket as the owner has not been active since may?

thecrafter06 if you want your request to be seen better by a mod go to the mojira discord here

Oh, okay.

Shouldn't a mod take ownership of this ticket? Only helpers and mods are updating this.

I don't think this is a bug, as this is intended behavior because the fortress is over a soul sand valley (which has few mob spawning). So majority of the mobcap is taken by the fortress mobs (no zombiefied piglins). That's why wither skeleton farms are very efficient in soul-sand valleys.

This is an issue, especially when the spawn rate is so high that you're swarmed by 6 wither skeletons and 6 blazes all at once, and as soon as you kill them you turn around, walk back, and there's 6 more to merk your face.

Strange thing, I can't seem to replicate even though this is confirmed. I ran around for around an hour waiting for mobs to spawn and only got a couple blazes, very few withers and skeletons, and practically no zombie piglins; it seemed the rate was low, possibly even more than normal. It was in the basalt delta biome, though, so maybe that affected it.

So I generated a new fortress in the soul sand valley biome, and sure enough, it does depend on the biome. Extremely high spawn rates, especially compared to my other fortress which is in the nether wastes and basalt delta biome.

Does this occur in warped forest biomes as well, or just soul sand valleys?

Can confirm for 1.17.1 Prelease 1.

To me, this only seems to occur in soul sand valleys. I have a fortress partially on a warped forest and the spawn rate is normal. Though according to gaspoweredpick's comment, it happens on all biomes.