Avoid TO_DATE casting when data type already is DATE

Looker Q&A Looker
1

This is the LookML

  dimension_group: dt {
    type: time
    timeframes: [
      date,
      month,
      quarter,
      year
    ]
    convert_tz: no
    datatype: date
    sql: ${TABLE}."DT" ;;
  }

and this is the generated SQL when including date

SELECT
    (TO_CHAR(TO_DATE(datamart."DT" ), 'YYYY-MM-DD')) AS "datamart.dt_date",

The DT column in the database table is of data type DATE, so why does Looker generate TO_DATE and is it possible to get it to not do that?