SELECT col, now() … ORDER BY 2 throws The query is not order by identifiers in SelectionPartiallyOrderedByDescOperation #19701

java.lang.IllegalArgumentException: The query is not order by identifiers
  at org.apache.pinot.core.operator.query.SelectionPartiallyOrderedByDescOperation.<init>(SelectionPartiallyOrderedByDescOperation.java:52)
  at org.apache.pinot.core.plan.SelectionPlanNode.run(SelectionPlanNode.java:100)
Same failure for ORDER BY 2, ORDER BY 2 ASC, ORDER BY 2 DESC, and ORDER BY now().

SELECT col, now() AS t
FROM my_table
ORDER BY 2 DESC
LIMIT 1;

SELECT now() AS t
FROM my_table
ORDER BY 1 DESC
LIMIT 1;

SELECT col, now() AS t
FROM my_table
ORDER BY col DESC
LIMIT 1;