By general bibliography standards and Endnote’s bibliography sort criteria, articles such as “the” are omitted from sorting in favor of the next word in the title – so this is actually correct.
Since you say you’re in the hurry, the quickest way to reverse order the two Medina bibliography entries is to convert a copy of your paper to text format (in order to remove the Endnote field codes) then manually switch the order by copying and pasting and changing the disambiguation (”a” to “b”, and vice versa).