Flesh to Stone not stolen despite being hit by it

[DarkSkullDemon]

I have tried stealing the power "Flesh to Stone" from the fight against Auren but was unable to despite being hit by it in mirror stance.
Attached are two screenshots

 

[Papum]

Sometimes even being hit does't mean it will automaticly be learned as i think it might be an chance on hit to be learn.
Have happened to me some times in the past aswell whit spells i wanted, as the enemy would have to hit me several times before it would be properly learned.
Keep trying eventually you will get it.