"Siri" won't set defined scene, "Hey Siri" will set scene

Ever since "Siri" was rolled out (vs. having to say "Hey, Siri") my Homepod mini has had an issue. I have a scene called "Bedtime", that shuts the house down.

If I say "Siri - bedtime" Siri replies "Good Night!" and does NOT execute the scene

If I say "Hey Siri - Bedtime", Siri replies "setting the scene" and executes the scene.

It's repeatable and has been constant through every update since they introduced the "Siri" command. Am I missing something about the Siri command?