Welcome to the Roku Community, @cliff_solomon!
Thank you for letting us know about the issue you've encountered in your Roku remote's voice command being unable to work. We'd be happy to provide further information about this.
Please be informed that the Roku remote's voice command feature works for Roku settings and only certain apps allow this to work inside their system. In this case, I believe that this feature is not allowed inside the Spotify app.
I hope you find this information helpful.
Best regards,
Carly
Carly Y.
Roku Community Moderator