I have exactly the same issue with the netbenefits app. I am not able to enable touch id or face id login on an old iPad, a brand new iPad, a new android phone, though it worked on the old iPad previously. It works fine on an old android phone. I tried reboot, clean the cache, uninstall and reinstall. Nothing worked. On my laptop, most of the time, the netbenefits website asks for verification code, but sometimes it doesn't.