updateRingGroup graphql fails and destroys data

The updateRingGroup graphql mutation appears to be broken and silently destroys data.

With the following graphql query (where groupNumber 2023 exists):

mutation update {
      updateRingGroup(
          input: {
              groupNumber: 2023
              extensionList: "12223#-333"
          }
      ) {
          status
          message
      }
  }

An error is returned:

{
   "errors": [
    {
      "message": "Internal server error",
       "status": false
    }
   ]
}

The logs say:

2023-01-22 20:10:36 - stdClass Object
(
    [debugMessage] => Undefined index: desc
    [message] => Internal server error
    [extensions] => stdClass Object
        (
            [category] => internal
        )

    [locations] => Array
        (
            [0] => stdClass Object
                (
                    [line] => 2
                    [column] => 7
                )

        )

    [path] => Array
        (
            [0] => updateRingGroup
        )

)

Further info:

It seems that specifying the 'description' in the mutation gets round the error