(2k3) Skills unusable

[Tachyglossus]

Problem: Some skills assigned to a character are unusable in battle, while others work.  There is no error, they are simply grayed out.

Information: The skills are assigned to a custom skill subset.  Each one is assigned to the correct type.  Animations are assigned.  The character has enough MP to cast the skills.  However, the skills are gotten through a class change that happens in game.  I do not see a reason for the skills to be unusable, which has left me perplexed.

Help would be appreciated.  If you need to know more, just ask.