Protector Scimitar - Heal in Combat Bug

Hi,
How do I use the Protector Scimitar's Heal ability that I received from the grey goblins in combat? Is this is a bug that I can not use it? I am able to use it out of combat, but not during combat. I understand its only 1 use per battle, but you need the heal the most in combat. I have the item equipped.
Thanks
How do I use the Protector Scimitar's Heal ability that I received from the grey goblins in combat? Is this is a bug that I can not use it? I am able to use it out of combat, but not during combat. I understand its only 1 use per battle, but you need the heal the most in combat. I have the item equipped.
Thanks