Consultative transfer of phone calls not possible anymore

Let me add a detail.
If you transfer a call coming from a regular Teams client, it works, as I said.

If you transfer a call coming from a telephone (associated with an application instance), then the attached commsNotification is received after the transferAccepted notification. The referenced call is the transfered one.

This does not come, when using a Teams client instead of a phone.

This message is not documented and new since the 8th June. 

@odata.type: "#microsoft.graph.commsNotifications"
    value: [
      {
        "@odata.type": "#microsoft.graph.commsNotification",
        "changeType": "updated",
        "resource": "/app/calls/7c1f5c00-1d34-42a4-9a3f-0d77b1d9baf1",
        "resourceUrl": "/communications/calls/7c1f5c00-1d34-42a4-9a3f-0d77b1d9baf1",
        "resourceData": {
          "@odata.type": "#microsoft.graph.call",
          "state": "established",
          "resultInfo": {
            "@odata.type": "#microsoft.graph.resultInfo",
            "code": 400,
            "subcode": 8538,
            "message": "CallEndReasonLocalUserInitiated. DiagCode: 603#0"
          },
          "callChainId": "95f09401-721e-4751-bde6-8e34d61e5d23",
          "replacesContext": "aHR0cHM6Ly9jYy1mcmNlLTA2LmNjLnNreXBlLmNvbS9jYy92MS9jYWxsUGFydGljaXBhbnQvNTgyNTc3OTctNjMxOC00NWQwLWE0ZWItYmJiYjQ2Mzg4NDFjLzEwL2szLzI1Mi9yZXBsYWNlbWVudD9ydD0yN2ExYzY1ZTIwZjE0MDUwYjFhYjVlYWJjNzA5ZGM2MiZyYz1leUp5ZEd4aWNtTWlPbnNpYVhCa2FYUmpJanBtWVd4elpTd2ljSE4wSWpvaVEyRnNiR2x1WjFCc1lXNXpJbjBzSW5KMGFXUWlPaUkwT2lzME9URTFOelU0TkRneE16WTFJbjAlMjUzZCZpPTE0NSZlPTYzNzU3NTcyOTYwNDE0OTI2Mg=="
        }
      }
    ]