So, I needed to make a new world because my dungeon didn't spawn with the different tile sets. However, in this new world, I've defeated all of the bosses at least once in hardmode and no bulb has spawned in the jungle. I've killed the twins once, destroyer five times and something robot skull once. Is there something I'm missing? I just build a spot for all my NPC's if that has something to with the bulb but I don't think it does. Halp, please.
While I can't help, I can say that I ran into this problem too. I made a new world because my original temple didn't spawn with an altar in it, and at the time I thought the Temple Key only dropped off of the first Plantera kill (I know, it drops every time, I was just too lazy to look it up >_>)
Couldn't find a bulb for the life of me, or even any chlorophyte ore, even though I went and activated hardmode and fought a mechanical boss.
So yeah, it might be a bug. Or yeah, maybe we were both stupidly unlucky >_>. One of those, probably.
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I'm so tired of looking I'm using MoreTerra. It's not showing up at all. My main world has about 30 bulbs.
A possibility: Have you killed the Queen Bee in the world with no bulbs?
Killing a Mechanical boss is said to be the requirement, but a few people did that Hardmode worlds that were otherwise untouched, and had no bulbs. But once they killed the Queen Bee as well, they found some bulbs in areas they had been too recently!
I dunno if that could help at all, but it is worth a try if you haven't done so already at least :x
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The bulb does seem to be prone to errors. I beat plantera about 30 times to get his trophy and along the way after my 23 kill or so the bulb did not spawn. So I ended up summoning and killing a different boss to force the bulb to spawn again. I killed plantera and a new bulb did not spawn, so I had to repeat the above steps until it happened a third time. At which point I created a new world in order to find a bulb and eventually get the trophy after a few more kills.
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