PWA on Android Firefox : Favicon is not showing on screen

Question

I just set up icons using a generator, and it almost works. When I launch my site in a Firefox browser for example, I see the intended favicon in the tab.

But when I use Firefox on Android, and I use the feature "Install", what I get on my home screen is a circle with the first letter of the app, as if I had no favicon.

Fun : when I put my phone on airplane mode, I can use the "add to homescreen" feature. And it that case, it works, I get the right icon on my home screen.

The manifest.json :

{
    "name": "Super app",
    "display": "standalone",
    "start_url": "super_url",

    "icons": [
        {
            "src": "/icon.svg",
            "sizes": "512x512",
            "type": "image/svg+xml"
        },
        {
            "src": "/android-512-512.png",
            "sizes": "512x512",
            "type": "image/png"
        },
        {
            "src": "/android-192-192.png",
            "sizes": "192x192",
            "type": "image/png"
        },
        {
            "src": "/android-144-144.png",
            "sizes": "144x144",
            "type": "image/png"
        },
        {
            "src": "/android-96-96.png",
            "sizes": "96x96",
            "type": "image/png"
        },
        {
            "src": "/android-72-72.png",
            "sizes": "72x72",
            "type": "image/png"
        },
        {
            "src": "/android-48-48.png",
            "sizes": "48x48",
            "type": "image/png"
        },
        {
            "src": "/favicon-32x32.png",
            "sizes": "32x32",
            "type": "image/png"
        },
        {
            "src": "/favicon-16x16.png",
            "sizes": "16x16",
            "type": "image/png"
        }
    ]
}

the relevant part of my Html head :

<link rel="apple-touch-icon" sizes="180x180" href="icons/apple-touch-icon.png">
<link rel="icon" type="image/png" sizes="32x32" href="icons/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="icons/favicon-16x16.png">
<link rel="mask-icon" href="icons/safari-pinned-tab.svg" color="#5bbad5">
<link rel="manifest" href="icons/manifest.json">