Program: 177309
Project: 177309
Buggy source:
/** 
 * Remove all batch at the specified position
 * @param x
 * @param y
 * @param z
 */
private void cleanBatchAggregator(Vector3 position,ChunkMesh chunkMesh){
  Map<RenderMaterial,Map<BlockFace,ChunkMeshBatchAggregator>> aggregatorPerMaterial=chunkRenderersByPosition.get(position.getFloorX(),position.getFloorY(),position.getFloorZ());
  if (aggregatorPerMaterial != null) {
    LinkedList<RenderMaterial> materialToRemove=new LinkedList<RenderMaterial>();
    for (    Entry<RenderMaterial,Map<BlockFace,ChunkMeshBatchAggregator>> entry : aggregatorPerMaterial.entrySet()) {
      RenderMaterial material=entry.getKey();
      LinkedList<BlockFace> faceToRemove=new LinkedList<BlockFace>();
      List<ChunkMeshBatchAggregator> chunkRenderer=chunkRenderers.get(material);
      for (      Entry<BlockFace,ChunkMeshBatchAggregator> entry2 : entry.getValue().entrySet()) {
        BlockFace face=entry2.getKey();
        ChunkMeshBatchAggregator batch=entry2.getValue();
        batch.setSubBatch(chunkMesh.getSubX(),chunkMesh.getSubY(),chunkMesh.getSubZ(),null);
        if (batch.isEmpty()) {
          batch.finalize();
          dirties.remove(batch);
          chunkRenderer.remove(batch);
          faceToRemove.add(face);
        }
      }
      for (      BlockFace face : faceToRemove)       entry.getValue().remove(face);
      if (entry.getValue().isEmpty())       materialToRemove.add(material);
      if (chunkRenderer.isEmpty())       chunkRenderers.remove(material);
    }
    for (    RenderMaterial material : materialToRemove)     aggregatorPerMaterial.remove(material);
    if (aggregatorPerMaterial.isEmpty())     chunkRenderersByPosition.remove(position.getFloorX(),position.getFloorY(),position.getFloorZ());
  }
}

Fixed version (ground truth):
/** 
 * Remove all batch at the specified position
 * @param x
 * @param y
 * @param z
 */
private void cleanBatchAggregator(Vector3 position,ChunkMesh chunkMesh){
  Map<RenderMaterial,Map<BlockFace,ChunkMeshBatchAggregator>> aggregatorPerMaterial=chunkRenderersByPosition.get(position.getFloorX(),position.getFloorY(),position.getFloorZ());
  if (aggregatorPerMaterial != null) {
    LinkedList<RenderMaterial> materialToRemove=new LinkedList<RenderMaterial>();
    for (    Entry<RenderMaterial,Map<BlockFace,ChunkMeshBatchAggregator>> entry : aggregatorPerMaterial.entrySet()) {
      RenderMaterial material=entry.getKey();
      LinkedList<BlockFace> faceToRemove=new LinkedList<BlockFace>();
      List<ChunkMeshBatchAggregator> chunkRenderer=chunkRenderers.get(material);
      for (      Entry<BlockFace,ChunkMeshBatchAggregator> entry2 : entry.getValue().entrySet()) {
        BlockFace face=entry2.getKey();
        ChunkMeshBatchAggregator batch=entry2.getValue();
        batch.setSubBatch(chunkMesh.getSubX(),chunkMesh.getSubY(),chunkMesh.getSubZ(),null);
        if (ChunkMesh.UNLOAD_ACCELERATOR || batch.isEmpty()) {
          batch.finalize();
          dirties.remove(batch);
          chunkRenderer.remove(batch);
          faceToRemove.add(face);
        }
      }
      for (      BlockFace face : faceToRemove)       entry.getValue().remove(face);
      if (entry.getValue().isEmpty())       materialToRemove.add(material);
      if (chunkRenderer.isEmpty())       chunkRenderers.remove(material);
    }
    for (    RenderMaterial material : materialToRemove)     aggregatorPerMaterial.remove(material);
    if (aggregatorPerMaterial.isEmpty())     chunkRenderersByPosition.remove(position.getFloorX(),position.getFloorY(),position.getFloorZ());
  }
}