Sarah's strength

[kpax]

I am in the Marshlands with sarah , guanidia, and baretta. After each battle sarahs strength shows as 2 numbers one in black and a lower one in red. I sense something is making her redline and she is the only character that does it. Can someone please explain what is going on?

[kpax]

Sorry! This has already been answered! Yes I can read contrary to present evidence! Thanks guys, I am enjoying the game.

[Keksich]

Wait, where is it answered?! I have the same problem!

[Mystsong]

It's the geomancy skill.