I know. But whatever they brought over didn't sync up correctly. The coda to the story is that just resetting the 2FA and having them scan/connect worked perfectly.
I think the thing that prompted me was that this (very abbreviated above) conversation took a lot longer with them insisting that nothing had changed. There was that one key piece of evidence though...
Semi-related, I've found that my Authenticator is a bit squirrely recently too - seems the time sync doesn't match up to my PC some of the time. But yes, in a normal world, transfers have worked before.