Program: 177256
Project: 177256
Buggy source:
@Override public void preSnapshotRun(){
  entityManager.preSnapshotRun();
  Point playerPosition=null;
  int renderLimit=Spout.getPlatform() == Platform.CLIENT && getRenderer() != null ? RENDER_QUEUE_LIMIT - (getRenderer().getBatchWaiting() + renderChunkQueue.size()) : 0;
  if (Spout.getEngine().getPlatform() == Platform.CLIENT) {
    SpoutClientWorld world=(SpoutClientWorld)this.getWorld();
    boolean worldRenderQueueEnabled=world.isRenderQueueEnabled();
    boolean firstRenderQueueTick=(!renderQueueEnabled) && worldRenderQueueEnabled;
    boolean unloadRenderQueue=!worldRenderQueueEnabled && renderQueueEnabled;
    SpoutPlayer player=((SpoutClient)Spout.getEngine()).getPlayer();
    if (player == null) {
      playerPosition=null;
    }
 else {
      playerPosition=player.getScene().getPosition();
    }
    if (firstRenderQueueTick && player != null) {
      for (      SpoutChunk c : player.getObservingChunks()) {
        c.setRenderDirty(true);
      }
      renderQueueEnabled=worldRenderQueueEnabled;
    }
    if (unloadRenderQueue) {
      for (      SpoutChunk c : rended.toArray(new SpoutChunk[rended.size()])) {
        addUpdateToRenderQueue(playerPosition,c,false,false,false);
      }
    }
  }
  SpoutChunk spoutChunk;
  List<SpoutChunk> renderLater=new LinkedList<SpoutChunk>();
  System.out.println("String_Node_Str");
  while ((spoutChunk=dirtyChunkQueue.poll()) != null) {
    if (renderQueueEnabled) {
      if (spoutChunk.isInViewDistance() || (spoutChunk.isRendered() && spoutChunk.leftViewDistance())) {
        if (renderLimit > 0) {
          addUpdateToRenderQueue(playerPosition,spoutChunk,spoutChunk.isBlockDirty(),spoutChunk.isLightDirty(),false);
          renderLimit--;
        }
 else {
          renderLater.add(spoutChunk);
        }
      }
 else {
        spoutChunk.setRenderDirty(false);
        spoutChunk.viewDistanceCopy();
      }
    }
    if (spoutChunk.isDirty()) {
      if (Spout.getPlatform() == Platform.SERVER) {
        for (        Player entity : spoutChunk.getObservingPlayers()) {
          syncChunkToPlayer(spoutChunk,entity);
        }
      }
      processChunkUpdatedEvent(spoutChunk);
      spoutChunk.resetDirtyArrays();
      spoutChunk.setLightDirty(false);
    }
  }
  for (  SpoutChunk c : renderLater) {
    c.setRenderDirty(true);
  }
  SpoutChunkSnapshotFuture snapshotFuture;
  while ((snapshotFuture=snapshotQueue.poll()) != null) {
    snapshotFuture.run();
  }
  renderSnapshotCacheBoth.clear();
  renderSnapshotCacheLight.clear();
  renderSnapshotCacheBlock.clear();
  for (int dx=0; dx < CHUNKS.SIZE; dx++) {
    for (int dy=0; dy < CHUNKS.SIZE; dy++) {
      for (int dz=0; dz < CHUNKS.SIZE; dz++) {
        SpoutChunk chunk=chunks[dx][dy][dz].get();
        if (chunk != null) {
          chunk.updateExpiredObservers();
        }
      }
    }
  }
  entityManager.syncEntities();
}

Fixed version (ground truth):
@Override public void preSnapshotRun(){
  entityManager.preSnapshotRun();
  Point playerPosition=null;
  int renderLimit=Spout.getPlatform() == Platform.CLIENT && getRenderer() != null ? RENDER_QUEUE_LIMIT - (getRenderer().getBatchWaiting() + renderChunkQueue.size()) : 0;
  if (Spout.getEngine().getPlatform() == Platform.CLIENT) {
    SpoutClientWorld world=(SpoutClientWorld)this.getWorld();
    boolean worldRenderQueueEnabled=world.isRenderQueueEnabled();
    boolean firstRenderQueueTick=(!renderQueueEnabled) && worldRenderQueueEnabled;
    boolean unloadRenderQueue=!worldRenderQueueEnabled && renderQueueEnabled;
    SpoutPlayer player=((SpoutClient)Spout.getEngine()).getPlayer();
    if (player == null) {
      playerPosition=null;
    }
 else {
      playerPosition=player.getScene().getPosition();
    }
    if (firstRenderQueueTick && player != null) {
      for (      SpoutChunk c : player.getObservingChunks()) {
        c.setRenderDirty(true);
      }
      renderQueueEnabled=worldRenderQueueEnabled;
    }
    if (unloadRenderQueue) {
      for (      SpoutChunk c : rended.toArray(new SpoutChunk[rended.size()])) {
        addUpdateToRenderQueue(playerPosition,c,false,false,false);
      }
    }
  }
  SpoutChunk spoutChunk;
  List<SpoutChunk> renderLater=new LinkedList<SpoutChunk>();
  while ((spoutChunk=dirtyChunkQueue.poll()) != null) {
    if (renderQueueEnabled) {
      if (spoutChunk.isInViewDistance() || (spoutChunk.isRendered() && spoutChunk.leftViewDistance())) {
        if (renderLimit > 0) {
          addUpdateToRenderQueue(playerPosition,spoutChunk,spoutChunk.isBlockDirty(),spoutChunk.isLightDirty(),false);
          renderLimit--;
        }
 else {
          renderLater.add(spoutChunk);
        }
      }
 else {
        spoutChunk.setRenderDirty(false);
        spoutChunk.viewDistanceCopy();
      }
    }
    if (spoutChunk.isDirty()) {
      if (Spout.getPlatform() == Platform.SERVER) {
        for (        Player entity : spoutChunk.getObservingPlayers()) {
          syncChunkToPlayer(spoutChunk,entity);
        }
      }
      processChunkUpdatedEvent(spoutChunk);
      spoutChunk.resetDirtyArrays();
      spoutChunk.setLightDirty(false);
    }
  }
  for (  SpoutChunk c : renderLater) {
    c.setRenderDirty(true);
  }
  SpoutChunkSnapshotFuture snapshotFuture;
  while ((snapshotFuture=snapshotQueue.poll()) != null) {
    snapshotFuture.run();
  }
  renderSnapshotCacheBoth.clear();
  renderSnapshotCacheLight.clear();
  renderSnapshotCacheBlock.clear();
  for (int dx=0; dx < CHUNKS.SIZE; dx++) {
    for (int dy=0; dy < CHUNKS.SIZE; dy++) {
      for (int dz=0; dz < CHUNKS.SIZE; dz++) {
        SpoutChunk chunk=chunks[dx][dy][dz].get();
        if (chunk != null) {
          chunk.updateExpiredObservers();
        }
      }
    }
  }
  if (Spout.getPlatform() == Platform.SERVER) {
    entityManager.syncEntities();
  }
}