Seems to work for me. The checking site acts weird though. The first time I searched it wasn't finding much, but I made it start over and it says it found it on dozens of relays more than I use in the client.
Discussion
it can be intermittent ! also local client settings and/or client app itself can interfere
I ran the same event ID through the checker again just now and it's on 162 relays now, so it's definitely working. Maybe it was just a little slow this morning.
i have notice similar behav based on client to post the note used but relays sets r tied to npub profile same 17 relay vs 178 relay found big diff
Where do you check this?