Program: 59915
Project: 59915
Buggy source:
@Override public void updateEntity(){
  super.updateEntity();
  checkForAdjacentPresents();
  float f;
  if (!worldObj.isRemote && numPlayersUsing != 0 && (+xCoord + yCoord + zCoord) % 200 == 0) {
    numPlayersUsing=0;
    f=5.0F;
    List list=worldObj.getEntitiesWithinAABB(EntityPlayer.class,AxisAlignedBB.getBoundingBox(xCoord - f,yCoord - f,zCoord - f,(xCoord + 1) + f,(yCoord + 1) + f,(zCoord + 1) + f));
    Iterator iterator=list.iterator();
    while (iterator.hasNext()) {
      EntityPlayer player=(EntityPlayer)iterator.next();
      if (player.openContainer instanceof ContainerPresent) {
        IInventory inventory=((ContainerPresent)player.openContainer).getLowerPresentInventory();
        if (inventory == this || inventory instanceof InventoryLargePresent && ((InventoryLargePresent)inventory).isPartOfLargePresent(this)) {
          ++numPlayersUsing;
        }
      }
    }
  }
  prevLidAngle=lidAngle;
  f=0.1F;
  double d2;
  if (numPlayersUsing > 0 && lidAngle == 0.0F && adjacentChestZNeg == null && adjacentChestXNeg == null) {
    double d1=xCoord + 0.5D;
    d2=xCoord + 0.5D;
    if (adjacentChestZPos != null) {
      d2+=0.5D;
    }
    if (adjacentChestXPos != null) {
      d1+=0.5D;
    }
    worldObj.playSoundEffect(d1,yCoord + 0.5D,d2,"String_Node_Str",0.5F,worldObj.rand.nextFloat() * 0.1F + 0.9F);
  }
  if (numPlayersUsing == 0 && lidAngle > 0.0F || numPlayersUsing > 0 && lidAngle < 1.0F) {
    float f1=lidAngle;
    if (numPlayersUsing > 0) {
      lidAngle+=f;
    }
 else {
      lidAngle-=f;
    }
    if (lidAngle > 1.0F) {
      lidAngle=1.0F;
    }
    float f2=0.5F;
    if (lidAngle < f2 && f1 >= f2 && adjacentChestZNeg == null && adjacentChestXNeg == null) {
      d2=xCoord + 0.5D;
      double d0=zCoord + 0.5D;
      if (adjacentChestZPos != null) {
        d0+=0.5D;
      }
      if (adjacentChestXPos != null) {
        d2+=0.5D;
      }
      worldObj.playSoundEffect(d2,yCoord + 0.5D,d0,"String_Node_Str",0.5F,worldObj.rand.nextFloat() * 0.1F + 0.9F);
    }
    if (lidAngle < 0.0F) {
      lidAngle=0.0F;
    }
  }
}

Fixed version (ground truth):
@Override public void updateEntity(){
  super.updateEntity();
  checkForAdjacentPresents();
  float f;
  if (!worldObj.isRemote && numPlayersUsing != 0 && (+xCoord + yCoord + zCoord) % 200 == 0) {
    numPlayersUsing=0;
    f=5.0F;
    List<?> list=worldObj.getEntitiesWithinAABB(EntityPlayer.class,AxisAlignedBB.getBoundingBox(xCoord - f,yCoord - f,zCoord - f,(xCoord + 1) + f,(yCoord + 1) + f,(zCoord + 1) + f));
    Iterator<?> iterator=list.iterator();
    while (iterator.hasNext()) {
      EntityPlayer player=(EntityPlayer)iterator.next();
      if (player.openContainer instanceof ContainerPresent) {
        IInventory inventory=((ContainerPresent)player.openContainer).getLowerPresentInventory();
        if (inventory == this || inventory instanceof InventoryLargePresent && ((InventoryLargePresent)inventory).isPartOfLargePresent(this)) {
          ++numPlayersUsing;
        }
      }
    }
  }
  prevLidAngle=lidAngle;
  f=0.1F;
  double d2;
  if (numPlayersUsing > 0 && lidAngle == 0.0F && adjacentChestZNeg == null && adjacentChestXNeg == null) {
    double d1=xCoord + 0.5D;
    d2=xCoord + 0.5D;
    if (adjacentChestZPos != null) {
      d2+=0.5D;
    }
    if (adjacentChestXPos != null) {
      d1+=0.5D;
    }
    worldObj.playSoundEffect(d1,yCoord + 0.5D,d2,"String_Node_Str",0.5F,worldObj.rand.nextFloat() * 0.1F + 0.9F);
  }
  if (numPlayersUsing == 0 && lidAngle > 0.0F || numPlayersUsing > 0 && lidAngle < 1.0F) {
    float f1=lidAngle;
    if (numPlayersUsing > 0) {
      lidAngle+=f;
    }
 else {
      lidAngle-=f;
    }
    if (lidAngle > 1.0F) {
      lidAngle=1.0F;
    }
    float f2=0.5F;
    if (lidAngle < f2 && f1 >= f2 && adjacentChestZNeg == null && adjacentChestXNeg == null) {
      d2=xCoord + 0.5D;
      double d0=zCoord + 0.5D;
      if (adjacentChestZPos != null) {
        d0+=0.5D;
      }
      if (adjacentChestXPos != null) {
        d2+=0.5D;
      }
      worldObj.playSoundEffect(d2,yCoord + 0.5D,d0,"String_Node_Str",0.5F,worldObj.rand.nextFloat() * 0.1F + 0.9F);
    }
    if (lidAngle < 0.0F) {
      lidAngle=0.0F;
    }
  }
}