The Grit Uptime needs to be adjusted when using the Great Axe passive “Enduring Strike”, the Greatsword passive “Unflinching Blade”, and the WH passive “Hardened Steel” while not having 300 attribute points allocated in Strength. There is a noticeable window of vulnerability you face when charging up a heavy attack with the aforementioned passives that does not exist when utilizing the 300 Strength Threshold Bonus for Grit when using Light and Heavy Attacks.
For the sake of consistency, make the Grit Uptime match that of the 300 Strength passive, thank you.