Circling back to the Akio/cap-tie conversation; I am 99.9% sure that Akio did in fact manage to inadvertently cap-tie himself to South Sudan with his appearances against Djibouti — those caps wouldn't have been an issue, had he been younger than 21 (ie. 20 or under)...
As far as I can tell, it's a combination of two specific rules at play:
AFCON Qualifying (as also pertains to other confederation competitions like the Gold Cup) matches do not fall under cap-tying appearances, as FIFA only counts matches played at the World Cup, in World Cup Qualifying, and in the final tournament proper of confederation competitions — under this rule, Akio would still eligible, but, combined with the age requirement element of Article 9.2 (c), he would've have to have been under 21 at the time of his last cap at senior 'A' international level (i.e. competitive, non-friendly matches) for him to be eligible for a switch; as his two matches against Djibouti were at age 23/24, he's no longer eligible under that rule (and also doesn't qualify under any others).
note - caveat emptor that it's now the n-th time that I've read the FIFA statues/articles and everything is starting to meld into one... but as far as I'm comprehending things, he unfortunately ruled himself out of a cap.