That means you missed her once. The 2nd time you find her she gives you only 4 MP. That means you missed her in either Tyrine or Moormore. If you missed her in Tyrine, you can't go back but if you missed her in Moormore you can go there and find her. Moormore's at the Eastern Lands of Adretana. Go to the transports, go to eastern lands and go east all the way.
"It's useless, it's all useless!!" - Ushiromiya Battler