I had a recent problem where I had already gotten to level 30, grabbed the Warrior Job, but was still behind in the story dungeons. I hit one that level capped me back down to 27, and while I was still warrior, it "greyed out" my Flash ability, and I couldn't use it. New to the game, I didn't understand it (and neither did the people with me, who have had more time with the game).
Later, when getting to the next dungeon, thinking on this fact and worrying about it, I went into the dungeon as Marauder instead of Warrior, which was a mistake, as the level capped at 31, and would have had Flash intact. But, we managed to make it through Haukke Manor (however it's spelled), without a "proper tank" or Defiance. Made it interesting during the last boss.