The fact that they continue to stack past a total die amount, unlike corrode markers that fall off into direct damage after you reach an armor max, leads me to believe that the effect is still cumulative. The rule is that the attacks can't be reduced to below one die, but if you then add dice like bear strength, charge, or bloodthirsty, you would still have to subtract the total amount of weaks from the new dice total to a mimimum of one die. The only way around this is if you somehow added dice after the roll dice step, which is impossible currently.
What i really wanna know though is how that bobcat got so many weak tokens without dying. Lol