If I select a smaller character with the same AI controller it will work perfectly.
I would post screen shots of your large and small characters and the movement components details along with collision and physics settings of those meshes. There is clearly something different, the computer doesn’t know what a “big” or “small” character is… only what you tell it so you must be telling it to move the big one slower by some script you have.
I found it is because rootmotion enabled.
Thank you for your help