Yeah. Not just Nova, all 3rd party launchers. It resets it after each restart. Hope Samsung fixes it sooner rather than later. Prefer a 3rd party launcher to the new UI as well.
settings, apps, default apps, clear out launcher home selection to none, exit to the home where you'll be prompted to open it with this or that, select desired launcher and select always.. let me know when done so I can walk you through settings changes to fix that next.