I agree: quiz fail.
Both “closed-minded” and “close-minded” appear in most of the on-line dictionaries I visited. (If anything, “closed-minded” seems to tend to get top billing.). ISTM that both usages are standard, so neither is wrong.
Per etymonline (not always a reliable source, admittedly, but the only one I could find with info about this) “close-minded” is attested to as early as 1818, while “closed-minded” is attested to in the 1880s. So, “close-minded” is indeed older, but “closed-minded” isn’t exactly a novel usage.