[Bug]: Superflat and Single biome worlds becoming regular worlds

[DragonJak]

General Info

• [X] I didn't add any mods
• [X] I can reproduce this issue consistently in single-player
• [ ] I can reproduce this issue consistently in multi-player
• [X] I have searched for this issue previously and it was either (1) not previously reported, or (2) previously fixed and I am having the same problem.
• [ ] I am crashing and can provide my crash report(s)
• [X] I am using the latest version of the modpack

Your launcher

Curseforge

Modpack version

2.5a

Describe your issue

So I'll load up a world in superflat with no structures, and the world will load normally. No matter how far I travel, it remains flat and full of slimes. But the moment I save and exit, then re-enter the game, the sky goes dark and if I run far enough, the world starts loading in the biomes like it normally does.

Steps to reproduce the issue

1. Create a superflat/single-biome world.
2. Save and quit
3. Re-open the save
4. Travel outside of whatever was loaded on the initial world spawn

Additional Information

I tried to do the same thing with a single biome deep dark world, and again, save/exiting then re-entering caused natural world generation to re-establish itself. Really makes challenge runs of this modpack quite difficult.

If a specific mod is doing this, that'd be great to know so I can remove it.

[DragonJak]

And what will that do?

[ScriptAero]

Do not click on that, mediafire links are floating around that have trojans in them