SQL Subquery not working

I tried the SQL subquery per the documentation here:
Complex Queries - Open Distro for Elasticsearch Documentation, Example 1: Table subquery:

SELECT m1.field1 from 
index_name m1
WHERE m1.field1 IN(
 Select m2.field1 from index_name m2 where m2.id = 100);

and I get the error:
no response, this query is not runnable.
The subquery when run as top-level works fine!
So is the subquery syntax supported in Opensearch or not?