Mine is doing the same thing. If you hold down on the camera app icon, go to app properties, force stop. I find this closes the app and stops the refining without a reboot. It's a pain that it does this now. Seemed to start after the last software update.
Another user susgested this and it worked for me:
"Go to Settings, device care, tap battery, then look for the camrea app, and make sure put to sleep option is turned off."
Hi as of the last update to my Verizon Galaxy Note 10+ anytime that I use the stock camera I have an ongoing refining picture notification that will only clear if I go into the camera settings in app management and force stop the camera.