Cannot use F-keys custom shortcuts

[touilleMan]

To reproduce:

1. go to "COSMIC Settings -> Input Devices -> Keyboard -> View and customize shortcuts -> Custom"
2. Click "Add shortcut"
3. Add any name and command
4. Input a F-key (typically F1 or F2)

Expected result: the list of custom shortcuts should contain the new shortcut Result: the list of custom shortcuts is not updated

Interestingly enough, the shortcut works just fine by manually editing ~/.config/cosmic/com.system76.CosmicSettings.Shortcuts/v1/custom:

{
    (
        modifiers: [],
        key: "F1",
    ): Spawn("tilda -T 0"),
}

However it is displayed as "Disabled" from the COSMIC Settings:

[BjornTheProgrammer]

Same problem here but with some special keys I have on my keyboard, notably the XF86Launch1 key.