Flaws with CREATE TRIGGER with ORed events including UPDATE OF

I have MariaDB 12.2.0.
The manual for CREATE TRIGGER does not mention multiple ORed events
https://mariadb.com/docs/server/server-usage/triggers-events/triggers/create-trigger
but MDEV-10164 is closed.
I say

CREATE TABLE t1 (s1 INT, s2 INT);

CREATE TRIGGER t1 BEFORE UPDATE OF s1 OR INSERT ON t1 FOR EACH ROW SET @a = @a + 1;

CREATE TRIGGER t1 BEFORE INSERT OR UPDATE OF s1 ON t1 FOR EACH ROW SET @a = @a + 1;

SELECT event_manipulation FROM information_schema.triggers WHERE trigger_name = 't1';

The first CREATE TRIGGER statement fails.
The second CREATE TRIGGER statement succeeds. This is inconsistent behaviour.
The SELECT returns "INSERT,UPDATE". This is incomplete information.

By the way, I intend to mention this feature (and any flaws) in a blog post soon.