I suggest you change it in Blender. It's generally recommended that Animations such as Walk, stay in one place. To quote from a forum post, Animation resets Character Controller:

"You don't want to animate things moving. You want to animate what they look like while they move. For example, a character walking is animated walking in place, not forward. To have a character walk, you play the 'walking in place' animation while the character controller moves forward, that's how a character walks forward."

And you move the Character Controller by an attached FPSWalker script.