The bug

Extinguishing fire by punching it while in creative mode plays fizz.ogg twice instead of once.

How to reproduce

Punch fire in creative mode. This may be easier to notice by creating a resource pack and replacing the extinguish sound (block.fire.extinguish) with a very short sound (such as random/wood_click):

• Create a folder in .minecraft/resourcepacks with any name (e.g. FireTest)
• In .minecraft/resourcepacks/FireTest, create a pack.mcmeta file with the following content (replace "3" with "4" for 1.13 snapshots):

  {
     "pack":{
        "pack_format":3,
        "description":"Test extinguishing fire sound bug (MC-19112)"
     }
  }
  

• In .minecraft/resourcepacks/FireTest/assets/minecraft, create a sounds.json file with the following content:

  {
    "block.fire.extinguish": {
      "replace": true,
      "sounds": [
        "random/wood_click",
        "mob/chicken/plop",
        "random/orb",
        "random/fizz"
      ]
    }
  }