Assassin's attack bug

Ive found another bug after testing out how buggy the assassins are...
im using dagger(mainhand)+sword(offhand), and my attack is 588(dagger), 638(sword)...
so, after using some scrolls and buff, i usually switch weapon cause the attack speed is bugged, then switch back again to have an attack speed of 0.9...
what ive notice is that my attack decreases both dagger and sword..
from : 588(dagger), 638(sword) switch weapon, and switch back agen
to : 526(dagger), 565(sword)...:surprised:
so, then i tried to unequiping my items and equipt agen, but the attack is the same, lowered..
also tried to relog, and found that is back to 588(dagger), 638(sword) attack.. then tried to switch "agen", and same thing happen... it lowered my attack to 526(dagger), 565(sword)..
i dont know if every assassin encounter this, but ive tried this many times already..