Spritesheet with a normal map loads texture twice

Version

Phaser Version: v3.55.2
Operating system: Linux
Browser: Google Chrome

Description

I try to load multiple textures with this.load.pack(). JSON file contains a section of spritesheets and one of them has a normal map included.

When I load the game browser shows the error: Texture key already in use: m4a1. I'm sure my JSON file doesn't contain the same key twice. Then I move a normalMap definition to the next image - the error now is: Texture key already in use: gun2.

This means generating sprites with normal map uses the same key twice somewhere.

:memo:	The example below is very basic, so the error happens once per 30-50 page refreshes, not every single time. In my bigger project this happens much more often

Detailed browser error:

 Texture key already in use: m4a1
checkKey @ phaser-arcade-physics-3.55.2.js:96888
addImage @ phaser-arcade-physics-3.55.2.js:97083
addToCache @ phaser-arcade-physics-3.55.2.js:16963
fileProcessComplete @ phaser-arcade-physics-3.55.2.js:189073
onProcessComplete @ phaser-arcade-physics-3.55.2.js:4961
data.onload @ phaser-arcade-physics-3.55.2.js:16931
load (async)
onProcess @ phaser-arcade-physics-3.55.2.js:16927
nextFile @ phaser-arcade-physics-3.55.2.js:189018
onLoad @ phaser-arcade-physics-3.55.2.js:4890
load (async)
XHRLoader @ phaser-arcade-physics-3.55.2.js:117741
load @ phaser-arcade-physics-3.55.2.js:4855
(anonymous) @ phaser-arcade-physics-3.55.2.js:188972
each @ phaser-arcade-physics-3.55.2.js:36745
checkLoadQueue @ phaser-arcade-physics-3.55.2.js:188958
update @ phaser-arcade-physics-3.55.2.js:188940
emit @ phaser-arcade-physics-3.55.2.js:1928
step @ phaser-arcade-physics-3.55.2.js:44529
update @ phaser-arcade-physics-3.55.2.js:95105
step @ phaser-arcade-physics-3.55.2.js:155129
step @ phaser-arcade-physics-3.55.2.js:84182
step @ phaser-arcade-physics-3.55.2.js:84429
requestAnimationFrame (async)
step @ phaser-arcade-physics-3.55.2.js:84431
requestAnimationFrame (async)
step @ phaser-arcade-physics-3.55.2.js:84431
requestAnimationFrame (async)
start @ phaser-arcade-physics-3.55.2.js:84483
start @ phaser-arcade-physics-3.55.2.js:84052
start @ phaser-arcade-physics-3.55.2.js:155074
texturesReady @ phaser-arcade-physics-3.55.2.js:155054
emit @ phaser-arcade-physics-3.55.2.js:1926
updatePending @ phaser-arcade-physics-3.55.2.js:96868
emit @ phaser-arcade-physics-3.55.2.js:1907
image.onload @ phaser-arcade-physics-3.55.2.js:96998
load (async)
addBase64 @ phaser-arcade-physics-3.55.2.js:96990
boot @ phaser-arcade-physics-3.55.2.js:96847
emit @ phaser-arcade-physics-3.55.2.js:1926
boot @ phaser-arcade-physics-3.55.2.js:155037
check @ phaser-arcade-physics-3.55.2.js:86801

Example Test Code

<!DOCTYPE html>
<html>
<head>
    <script src="files/phaser-arcade-physics-3.55.2.js"></script>
</head>
<body>

    <script>
    var config = {
        type: Phaser.AUTO,
        width: 800,
        height: 600,
        scene: {
            preload: preload,
            create:  create
        }
    };

    var game = new Phaser.Game(config);

    function preload ()
    {
        this.load.pack('assets', 'files/pack.json');
    }

    function create ()
    {
        gun = this.add.sprite(100, 100, 'm4a1');
    }
    </script>

</body>
</html>

pack.json content:

{
    "spritesheets": {
        "path": "files",
        "defaultType": "spritesheet",
        "files": [
            { "key": "m4a1", "url": "m4a1.png", "frameConfig": { "frameWidth": 58, "frameHeight": 21  }, "normalMap": "m4a1-normal.png" },
            { "key": "gun2", "url": "gun2.png", "frameConfig": { "frameWidth": 58, "frameHeight": 21  }}
        ]
    }
}

phaserjs / phaser