did you check the settings for the camera app? open the app and go to settings and there should be an option to enable QR code scanning.
if it's on but still doesn't work. then try to clear cache and data for the camera app.
You can also try uninstall and reinstall updates for the camera app (can't remember if the app lets you delete update tho, please check if it'll let you).
you can submit error report to samsung members after reproducing the issue once more, the engineers should be able to help furthur
Open the app, then settings, Layout and menu, Customize menu, drag QR code scanner icon to the "active" lower section of the screen.
Pro - you have a QR scanner
Con - it's on the Internet app but not on the Camera app.