Are you fully exiting Opus (via File / Exit Directory Opus), or just closing the window?
That setting only applies when Opus has been exited and is later re-started.
If you're just closing the window, turn on Preferences / Launching Opus / Default Lister / Update Default Lister automatically when closing a Lister and (if applicable) make sure whichever method you're using to open Opus windows will open the Default Lister and not any particular layout which would override it.