VInterp does not work with opposite vectors

I’m trying to make how my character moves more natural so, instead of use the input direction to add movement, I interpolate from Actor forward to input direction and I use that direction for input movement.

It’s working fine unless the input direction is opposite to actor forward vector. In that case the interpolation is not happening…

I’m drawing the input direction and the interpolated one, so when we tried to move in the opposite direction I can see clearly the input direction arrow and how the interpolated arrow does not move.

any idea?