Jetboil Burner Rattle?

[Staninator]

Hey guys, I just received a jetboil zip for Christmas and tested it out this morning for the first time. It lit up fine and boiled some water but when I turned down the burner, I hear some metallic crackling and when it was off, there was something rattling in the burner. When it cooled down, the rattling went away. It still turns on fine but I just want to check with those who already have one to make sure it's not defective and if it is, then I can contact Jetboil to get it figured out.