Mqtt scene config/discovery from addon not working

Tags: #<Tag:0x00007fc40a50f278> #<Tag:0x00007fc40a50f188>

Hi,
I’m trying to get mqtt scene discovery working triggered from addon, but can’t see any devices added to Home Assistant. Light discovery is working as expected. What have I missed?

Context
I am trying to move scenes from the mqtt/switch domain to mqtt/scene domain (does that make sense or is it better to just drop that?) in the hassio-plejd HA addon. It seems to me like the better place to place scenes, but it also seems no state updates will be possible (“scene was triggered by Plejd”). Code if someone wants to dig deep https://github.com/icanos/hassio-plejd/pull/179#issuecomment-814830881

Light discovery over mqtt works well, example below

Topic homeassistant/light/plejd/CD0C690DBCA9_0
{
  "schema": "json",
  "name": "Kök bänk",
  "unique_id": "CD0C690DBCA9_0",
  "~": "homeassistant/light/plejd/CD0C690DBCA9_0",
  "state_topic": "~/state",
  "command_topic": "~/set",
  "availability_topic": "~/availability",
  "optimistic": false,
  "qos": 1,
  "retain": true,
  "brightness": true,
  "device": {
    "identifiers": "CD0C690DBCA9",
    "manufacturer": "Plejd",
    "model": "DIM-01",
    "name": "Kök bänk",
    "sw_version": "2.0"
  }
}

Scene (not working)

Topic: homeassistant/scene/plejd/8914a5e6-8791-4ea3-9130-7971957544f8
{
  "name": "Släck plejd 🌠",
  "~": "homeassistant/scene/plejd/8914a5e6-8791-4ea3-9130-7971957544f8",
  "command_topic": "~/set",
  "optimistic": false,
  "qos": 1,
  "retain": true,
  "device": {
    "identifiers": "8914a5e6-8791-4ea3-9130-7971957544f8",
    "manufacturer": "Plejd",
    "model": "Scene",
    "name": "Släck plejd 🌠"
  }
}

Any ideas why this does not work? Or is it maybe not supposed to create any entities (like switches)?

Thanks!

In case anyone encounters mqtt discovery issues similar to this: Triple-check you have not added any extra keys. In the scene example “optimistic” and “device” keys are not supported.