diff --git a/src/main/java/ca/spottedleaf/moonrise/mixin/starlight/world/WorldGenRegionMixin.java b/src/main/java/ca/spottedleaf/moonrise/mixin/starlight/world/WorldGenRegionMixin.java
new file mode 100644
index 0000000..11c53b3
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/moonrise/mixin/starlight/world/WorldGenRegionMixin.java
@@ -0,0 +1,46 @@
+package ca.spottedleaf.moonrise.mixin.starlight.world;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.server.level.WorldGenRegion;
+import net.minecraft.world.level.LightLayer;
+import net.minecraft.world.level.WorldGenLevel;
+import net.minecraft.world.level.chunk.ChunkAccess;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+@Mixin(WorldGenRegion.class)
+public abstract class WorldGenRegionMixin implements WorldGenLevel {
+
+    @Shadow
+    public abstract ChunkAccess getChunk(int i, int j);
+
+    /**
+     * @reason During feature generation, light data is not initialised and will always return 15 in Starlight. Vanilla
+     * can possibly return 0 if partially initialised, which allows some mushroom blocks to generate.
+     * In general, the brightness value from the light engine should not be used until the chunk is ready. To emulate
+     * Vanilla behavior better, we return 0 as the brightness during world gen unless the target chunk is finished
+     * lighting.
+     * @author Spottedleaf
+     */
+    @Override
+    public int getBrightness(final LightLayer lightLayer, final BlockPos blockPos) {
+        final ChunkAccess chunk = this.getChunk(blockPos.getX() >> 4, blockPos.getZ() >> 4);
+        if (!chunk.isLightCorrect()) {
+            return 0;
+        }
+        return this.getLightEngine().getLayerListener(lightLayer).getLightValue(blockPos);
+    }
+
+    /**
+     * @reason See above
+     * @author Spottedleaf
+     */
+    @Override
+    public int getRawBrightness(final BlockPos blockPos, final int subtract) {
+        final ChunkAccess chunk = this.getChunk(blockPos.getX() >> 4, blockPos.getZ() >> 4);
+        if (!chunk.isLightCorrect()) {
+            return 0;
+        }
+        return this.getLightEngine().getRawBrightness(blockPos, subtract);
+    }
+}
diff --git a/src/main/resources/moonrise.mixins.json b/src/main/resources/moonrise.mixins.json
index f52a9cd..0f83592 100644
--- a/src/main/resources/moonrise.mixins.json
+++ b/src/main/resources/moonrise.mixins.json
@@ -58,6 +58,7 @@
     "starlight.world.ChunkSerializerMixin",
     "starlight.world.LevelMixin",
     "starlight.world.ServerWorldMixin",
+    "starlight.world.WorldGenRegionMixin",
     "util_thread_counts.UtilMixin",
     "util_threading_detector.ThreadingDetectorMixin",
     "util_time_source.UtilMixin"