[Derision]

After looking over this again, the call to SendPetBuffsToClient in Mob::BuffFadeByEffect is redundant, since BuffFadeByEffect calls BuffFadeBySlot, and the pet window buff packet is already sent in that routine.

So, after applying the patch, you can delete these lines:

spells.cpp, Line 2614:

void Mob::BuffFadeByEffect(int effectid, int skipslot)
{
        int i;

        for(i = 0; i < BUFF_COUNT; i++)
        {
                if(buffs[i].spellid == SPELL_UNKNOWN)
                        continue;
                if(IsEffectInSpell(buffs[i].spellid, effectid) && i != skipslot)
                        BuffFadeBySlot(i, false);
        }
        // Delete the following 3 lines as they are redundant.
        if(IsPet() && GetOwner() && GetOwner()->IsClient()) {    
                SendPetBuffsToClient();                                     
        }                                                                           
        //we tell BuffFadeBySlot not to recalc, so we can do it only once when were done
        CalcBonuses();
}