Hot to PUT and object?

Hi, I tried to update WooCommerce product meta_data via PUT or PATCH but always got a 400 eror. I used all possible formats for meta_data object but all were rejected with same message:

{
  "code": "rest_invalid_param",
  "message": "Invalid parameter(s): meta_data",
  "data": {
    "status": 400,
    "params": {
      "meta_data": "meta_data[0] is not of type object."
    },
    "details": {
      "meta_data": {
        "code": "rest_invalid_type",
        "message": "meta_data[0] is not of type object.",
        "data": {
          "param": "meta_data[0]"
        }
      }
    }
  }
}