Nova Launcher switches to One UI when i clear recent apps

Hi, I have a Samsung S10+ running Android 10 and One UI 2.5.

I am constantly getting an issue with Nova Launcher where if i clear my recent apps the screen refreshes and then One UI takes over and it goes to that home screen rather than Nova. If i then press the Home button again it then takes me back to Nova's home screen again and does stay there until i clear my recent apps again.

Nova is definitely set to the default launcher and when this happens i go into the Nova settings and it shows no launcher is set as default, i then set it as default but the same thing keeps happening each time.

I have tried clearing the cache from both Nova and One UI but this didn't fix anything.

Is this a know issue? It has happened for a while but wasn't that annoying but since a recent android update it seems to be happening all the time now.

Does anyone know if i can fix this?

Thanks

James