Thief ability not stealing item

[Wildflecken]

I was just hunting Quagsires in Dragons Den to get a Damp Stone.

With Furret's frisk ability I spotted a Quagsire having a Damp Stone and used Thief to steal it, but I do not have it in my inventory right now.

 

Edit: With inventory I mean Furrets held item.

Edit2: The second time it worked now, not sure what happened before