On https://wikitech.wikimedia.org/wiki/Special:Two-factor_authentication , I got my "Two-factor authentication secret key"; I produced a code for "Enter a code from your authentication device to verify" with oathtool -b "1234 5678 90AB CDEF" and entered it, submitted the page.
I. Expected: the page reloads with a warning that my code is not correct and that I probably made a mistake in producing it.
II. Observed: the page reloads identical, with no indication whatsoever that my request was even received or processed, and the text field still carrying the incorrect code (which encourages resubmit).
(By the way, because I know better, I used --totp and easily got things working; but there is no mention of TOTP on https://wikitech.wikimedia.org/wiki/Help:Two-factor_authentication or https://www.mediawiki.org/wiki/Help:Two-factor_authentication ; https://meta.wikimedia.org/wiki/Help:Two-factor_authentication mentions TOTP but not oathtool. Typical chi ha pane non ha denti situation.)