device_if behavior not symmetric with device_unless

[jamesonquinn]

KE v15.3.0
MacOS 14.6.1

Devices (copied from KEV/Devices):
[
{
"device_id": 4294969634,
"device_identifiers": { "is_keyboard": true },
"is_apple": true,
"is_built_in_keyboard": true,
"location_id": 176,
"manufacturer": "Apple",
"product": "Apple Internal Keyboard / Trackpad",
"transport": "FIFO"
},
{
"device_id": 4294969664,
"device_identifiers": { "is_pointing_device": true },
"is_apple": true,
"is_built_in_pointing_device": true,
"location_id": 176,
"manufacturer": "Apple",
"product": "Apple Internal Keyboard / Trackpad",
"transport": "FIFO"
},
{
"device_id": 4297095253,
"device_identifiers": {
"is_game_pad": true,
"is_keyboard": true,
"is_pointing_device": true,
"product_id": 29700,
"vendor_id": 3141
},
"location_id": 1249280,
"manufacturer": "PCsensor",
"product": "FootSwitch3-F1.8",
"transport": "USB"
},
{
"device_id": 4297167274,
"device_identifiers": {
"is_keyboard": true,
"is_virtual_device": true,
"product_id": 591,
"vendor_id": 1452
},
"manufacturer": "pqrs.org",
"product": "Karabiner DriverKit VirtualHIDKeyboard 1.8.0",
"serial_number": "pqrs.org:Karabiner-DriverKit-VirtualHIDKeyboard"
},
{
"device_id": 4297095745,
"device_identifiers": {
"is_pointing_device": true,
"product_id": 52,
"vendor_id": 7247
},
"location_id": 1253376,
"manufacturer": "SIGMACHIP",
"product": "Usb Mouse",
"transport": "USB"
}
]

I want pressing "a" on the FootSwitch3-F1.8 to result in "x". So here's one attempt at a complex modification:

{
"description": "pedals",
"manipulators": [
{
"conditions": [
{
"identifiers": [{ "is_game_pad": true }],
"type": "device_if"
}
],
"from": {
"key_code": "a",
"modifiers": { "optional": ["any"] }
},
"to": [{ "key_code": "x" }],
"type": "basic"
}
]
}

The above doesn't work; a=a on both internal keyboard and footswitch. However, if I change "device_if" to "device_unless", I do "successfully" get the reverse of the behavior I want; that is, a=x on internal keyboard, but a=a on footswitch.

Seems clear to me that this is some kind of bug.

(Note that using "is_game_pad" was not my first attempt; I was getting even-more-confusing behavior with "product_id" and "vendor_id". But this seems like a minimal, clear version of this bug.)

[tekezo]

I can't reproduce this on my end. With the following rule, the a key on the built-in keyboard is not modified.
Could there be another rule that is modifying the a key?

{
    "description": "pedals",
    "manipulators": [
        {
            "conditions": [
                {
                    "identifiers": [{ "is_game_pad": true }],
                    "type": "device_if"
                }
            ],
            "from": {
                "key_code": "a",
                "modifiers": { "optional": ["any"] }
            },
            "to": [{ "key_code": "x" }],
            "type": "basic"
        }
    ]
}