Program: 11711
Project: 11711
Buggy source:
public void tick(){
  ThreadsHandler.worldExecutor().execute(() -> {
    redstoneTick=!redstoneTick;
    long currentTime=time.get();
    rainTime.getAndDecrement();
    thunderTime.getAndDecrement();
    if (rainTime.get() <= 0) {
      raining=!raining;
      if (raining) {
        RainEvent e=EventProcessor.fire(new RainEvent(this));
        if (e.isIgnored()) {
          raining=false;
        }
      }
 else {
        SunEvent event=EventProcessor.fire(new SunEvent(this));
        if (event.isIgnored()) {
          raining=true;
        }
      }
      rainTime.set(ThreadLocalRandom.current().nextInt());
    }
    if (thunderTime.get() <= 0) {
      thundering=!thundering;
      if (thundering) {
        ThunderEvent e=EventProcessor.fire(new ThunderEvent(this));
        if (e.isIgnored()) {
          thundering=false;
        }
      }
 else {
        SunEvent event=EventProcessor.fire(new SunEvent(this));
        if (event.isIgnored()) {
          thundering=true;
        }
      }
      thunderTime.set(ThreadLocalRandom.current().nextInt());
    }
    boolean updateTime=(currentTime & 40) == 0;
    for (    Entity entity : entities) {
      TickSync.increment("String_Node_Str" + entity.uniqueId().toString() + "String_Node_Str"+ entity.entityId()+ "String_Node_Str"+ entity.type());
      ((TridentEntity)entity).tick();
      if (entity instanceof Player) {
        TridentPlayer player=(TridentPlayer)entity;
        if (updateTime) {
          player.connection().sendPacket(new PacketPlayOutTimeUpdate().set("String_Node_Str",existed.get()).set("String_Node_Str",currentTime));
        }
      }
    }
    if ((currentTime & CHUNK_EVICTION_TIME) == 0) {
      for (      ChunkLocation chunk : loadedChunks.keys()) {
        loadedChunks.tryRemove(chunk);
      }
    }
    if (currentTime >= 24000)     time.set(0);
 else     time.getAndIncrement();
    existed.getAndIncrement();
    TickSync.complete("String_Node_Str" + name());
  }
);
}

Fixed version (ground truth):
public void tick(){
  ThreadsHandler.worldExecutor().execute(() -> {
    redstoneTick=!redstoneTick;
    long currentTime=time.get();
    rainTime.getAndDecrement();
    thunderTime.getAndDecrement();
    if (rainTime.get() <= 0) {
      raining=!raining;
      if (raining) {
        RainEvent e=EventProcessor.fire(new RainEvent(this));
        if (e.isIgnored()) {
          raining=false;
        }
      }
 else {
        SunEvent event=EventProcessor.fire(new SunEvent(this));
        if (event.isIgnored()) {
          raining=true;
        }
      }
      rainTime.set(ThreadLocalRandom.current().nextInt());
    }
    if (thunderTime.get() <= 0) {
      thundering=!thundering;
      if (thundering) {
        ThunderEvent e=EventProcessor.fire(new ThunderEvent(this));
        if (e.isIgnored()) {
          thundering=false;
        }
      }
 else {
        SunEvent event=EventProcessor.fire(new SunEvent(this));
        if (event.isIgnored()) {
          thundering=true;
        }
      }
      thunderTime.set(ThreadLocalRandom.current().nextInt());
    }
    boolean updateTime=(currentTime & 40) == 0;
    for (    Entity entity : entities) {
      TickSync.increment("String_Node_Str" + entity.uniqueId().toString() + "String_Node_Str"+ entity.entityId()+ "String_Node_Str"+ entity.type());
      ((TridentEntity)entity).tick();
      if (entity instanceof Player) {
        TridentPlayer player=(TridentPlayer)entity;
        if (updateTime) {
          player.connection().sendPacket(new PacketPlayOutTimeUpdate().set("String_Node_Str",existed.get()).set("String_Node_Str",currentTime));
        }
      }
    }
    if ((currentTime & CHUNK_EVICTION_TIME) == 0) {
      UnmodifiableIterator<List<ChunkLocation>> list=Iterators.partition(loadedChunks.keys().iterator(),Math.max(TridentPlayer.players().size(),1));
      for (; list.hasNext(); ) {
        List<ChunkLocation> chunks=list.next();
        ThreadsHandler.chunkExecutor().execute(() -> chunks.forEach(loadedChunks::tryRemove));
      }
    }
    if (currentTime >= 24000)     time.set(0);
 else     time.getAndIncrement();
    existed.getAndIncrement();
    TickSync.complete("String_Node_Str" + name());
  }
);
}