default home app / launcher reset after Android 11 update

I had Nova Launcher installed and set as default. Yesterday I updated to Android 11. After the update there's a bit of mixup: mostly when I go back to the home screen, it presents the Nova Launcher as expected, but sometimes it drops me into the preinstalled launcher I stopped using long ago in favor of Nova. Pressing the home button again pops up the Nova Launcher. Device: Nokia 5.3 (Android One) How to properly fix this?