I have re-tested this and do believe there is a problem with the current version of NodeBB and the 2FA plugin.
Here on community.nodebb.org I am unable to generate backup 2FA codes. When I test this on my v1.0.2
NodeBB forum I am able to create 2FA codes. It seems that the problem is not dependent upon which 2FA app I use.
Would someone else who is using two factor authentication on this site please generate (or re-generate) their backup codes and see if after pressing the button to have them created they actually display on the screen. For me I press the button, my notification bell alerts but no codes are displayed to be copied.
Thank you.