Why my skill is receiving Alexa.Presentation.APL.UserEvent from TouchWrapper?

I have a skill that uses APL in a very simplistic manner - basically, if the device supports APL, it outputs an APL 1.1 document with some image and text. No interactive elements, lists, no touch wrappers.

I have noticed recently that very infrequently I receive an event that seems to come from a TouchWrapper:

...
"request": {
  "type": "Alexa.Presentation.APL.UserEvent",
  "requestId": "amzn1.echo-api.request.4d7bc45d-c1bc-4b25-bd23-fdcd27a7bb5d",
  "timestamp": "2020-12-08T15:18:07Z",
  "locale": "en-US",
  "arguments": [
    "goBack"
  ],
  "components": {},
  "source": {
    "type": "TouchWrapper",
    "handler": "Press",
    "id": "",
    "value": false
  },
  "token": ""
}
...

This is totally unexpected and my skill crashes. I thought I'd only receive a request like this if I output an APL screen with some interactive functionality.

In the past week, it happened only five times out of many hundreds of thousands of interactions, so it is very rare, but it is still worrying.

Does anyone know why I am receiving this request?

question