Rootmotion blendspace doesn't interpolate

oh, sry, I didn’t explain that I changing boost value(blendspace axis) by mouse wheel (± 10) just for debug.
At the begining I set it like loosing stamina and boost goes slowly from 100 to 40. And it didn’t interpolate.
You can see that speed is not changing while I change boost from 40 to 50 or from 60 to 70…