Fortified Stance and Toughness workin as intended?

[Xith]

<DIV> </DIV> <DIV>As a guardian I noticed when I cast 'toughness' when I had 'fortified stance' up that my mitigation would drop, and vice versa....then when Id cancel one of them my mitigation would shoot back up.</DIV> <DIV> </DIV> <DIV>From reading the skill descriptions it doesnt appear they should be canceling each other out...</DIV> <DIV> </DIV> <DIV>Its wierd, youd expect if you have Fortified stance up first then cast toughness and it was indeed cancelling the other out,..that youd lose all the benefits of F. Stance.... but you dont you just lose the amount that Toughness would of given you... so its like they are adding a negative value....but only when the two are up and not when its only one.</DIV> <DIV> </DIV> <DIV>So my question is, has anyone else noticed this? do you think its a bug or 'working as intended' ?</DIV>