Change_multiple_column_values for connect_board results in { "error_message": "Internal server error", "status_code": 500 }

For future note, I found this worked:

	let x = {
		"linkedPulseIds": [{
			"linkedPulseId": 2643558944
		}]
	}

	let mutation = `mutation {
  change_column_value(board_id: 2588471113,
    item_id: 2643558945,
    column_id: "connect_boards30",
    value: ${JSON.stringify(JSON.stringify(x))}) {
    id
    }
  }

Got it from here: Parsing Error: No error on playground, error in JavaScript