Structures Also Spawn in Neighboring Biomes

I've seen multiple structures of mine spawn outside of the selected biome. 

Minecraft Version 1.20.1, MCreator 2024.1

My structures are spawning fine in my selected biome, but they are also spawning in the neighboring biome which is not selected in the structure settings.

biome to generate structure in: my selected biome

structure chunk distribution: Separation: 4, Spacing 5

generation stage: SURFACE_STRUCTURES

type of ref ground detection: WORLD_SURFACE_WG

Terrain adaptation type: beard_thin

projection: terrain matching

jigsaw depth: 1

jigsaw max distance: 64

there is no jigsaw pool configuration.

Any help would be appreciated! It's weird to happen to these structures, is it the spacing? or jigsaw max distance? I want them to strictly spawn in the biome, but they are big structures and I would rather them not be features. Thanks!