Hit 29 couldn't get dire charge. All three martial destinies looked maxed (had the points). Had to select each one and put some xp in them. Ended up Grandmaster of Flowers wasn't quite maxed. Couple of ideas.
That would avoid this
1. Show numbers so you can see if you are maxed out
2. Have the xp bar at the top of the destiny change color if maxed out
3. Have it say max'd with a tool tip