I just tried to set up two way authentication from my desktop to my phone using the QR Reader (for this developer forum). After scanning the code with a 3rd party QR Reader, I was presented with the following screen:
I’m currently using an iOS device, version 11.4. I was surprised Google Authenticator wasn’t automatically opened, as it is currently on my phone for other apps. I eventually opened and added authentication directly through Google Authenticator, but was happy to see a manual code entry should that also fail to load. I wanted to document this as a potential bug regardless.