See this reddit post by mezz for a nice description of what the issue is and why it happens. At the very least your CropGenerator and probably the other bits of world generation as well are missing the +8 offset to the area being populated causing unloaded chunks to be generated recursively

We are seeing this happen again on 1.11.2 with Natura 4.2.0.16.
In that version there is a Forge log you can put a breakpoint at to help debug:
Natura loaded a new chunk (16, 24 Dimension: 0) during chunk population, causing cascading worldgen lag. Please report this to the mod's issue tracker. This log can be disabled in the Forge config.