Attribute modifiers only gives 1 attribute and applies minimum effects only

Items with multiple 'Attribute Modifier' only applies 1 attribute modifier and it's also set to minimum
Ex: Diamond Sword was given 2 Attribute Modifiers, generic.attack_damage with a value of 1000, and generic.attack_speed with the same value.
   When the game is reloaded, the diamond sword has the generic.attack_damage attribute but instead of 1 hitting an entity (since it's a 1000 atk damage), it took me 3 hit and applies to different values (1000+ values still gives me minimum effects of the attribute}. The second problem is that the second attribute is not applying. My second attribute was generic.attack_speed with the same value (1000) but instead of me having a modified, enhanced speed, it did not apply to me.