After I started to actively using /perf chunks command, I noticed that visited chunks not unloading.

For example, on this cut of overworld we could see recently visited chunks. Some of them are loaded, but others randomly kept loaded:

This chunks is just plain generated terrain, maybe with someone base in 5-6 chunks

I will post my investigation here just to find if someone know how to fix this issue.

For now, i tried to remove those mods, and this wont fix the issue:

• UniversalTweaks
• AIReducer
• RLTweaker
• Sledgehammer

You could try installing NoiseThreader
If this does not solve the problem, you can ask the author of this mod to fix this bug

You could try installing NoiseThreader If this does not solve the problem, you can ask the author of this mod to fix this bug

How does world generation related to chunk loading? This mod is irrelevant.