Noted.

I tried the following in both SQL Editor and Notebook and got the same outcome:

%sql
USE CATALOG my_catalog;

USE SCHEMA my_schema;

DROP MATERIALIZED VIEW IF EXISTS my_mv;

CREATE MATERIALIZED VIEW my_mv
  (col_1 STRING COMMENT 'Column 1', col_2 STRING COMMENT 'Column 2')
  COMMENT 'MV of a streaming table.'
AS (
  SELECT col_1 , col_2 FROM my_streaming_table
)