Can't completely disable two-step verification; Can't use new verification codes after disabling / re-enabling

I recently attempted to disable two-step verification, but continue to be redirected to the “6-digit verification code” screen.

Verification codes in my authenticator app no longer work, but I can still login using the 24-character emergency recovery key, save the new key and continue.

At this point, two-step verification is disabled. I tried re-enabling it, scanning the QR code, entering the current verification code to confirm, logging out, logging in and the verification codes don’t work. I then enter the emergency key, save the new one and continue.

At this point, two-step verification is enabled. I disable it, log out, log in, and again I’m redirected to the verification code screen. Rinse, repeat — same result from incognito windows. You can see the two-step enable/disable activities in my account’s audit log — the last being to disable it.

Right now I can continue to use the recovery key, save the new one and continue, but I’m wondering what I’m doing wrong, if there’s something not getting updated on my account or if there’s some timeframe I need to wait before the changes take effect.

Apologies if this is a dupe — I checked and didn’t find another issue describing this scenario.

Much appreciated.