Originally Posted by
Socrates1984
This has bugged me for some years now, but a solution has been found (not by me), providing consistent results so far. It is not a Hyrule specific problem, it's for the whole M2TW.
So. Retraining for XP works if it is the very last thing you do before pressing End Turn. The absolute last thing, including saving the game (I do it every turn). It works every single time both for retraining old units and recruiting new ones. I have developed a habit of worrying about units just before ending the turn.