Azure OpenAI service base models are not fine-tunable

Question

When creating a custom model from the UI, the base model dropdown list is empty. When I list models in Python SDK, models are showing fine_tune=false for all base models. See an example below. Has anyone run into this? How do I make a model fine-tunable?

{
      "capabilities": {
        "completion": true,
        "embeddings": false,
        "fine_tune": false,
        "inference": false,
        "scale_types": [
          "manual"
        ]
      },
      "created_at": 1646092800,
      "deprecation": {
        "fine_tune": 1709251200,
        "inference": 1709251200
      },
      "id": "ada",
      "lifecycle_status": "preview",
      "object": "model",
      "status": "succeeded",
      "updated_at": 1646092800
    }

I expect base models are fine-tunable out of box.