I’ve got a problem with my rotate root bone and my yaw. basically when I mulitply my yaw by 1 it will rotate the root bone using the Z axis and when I multiply it by 0 it will be rotating in the Y axis, which should also be the axis it should be rotating around when I multiply it by 1 but it doesn’t so does anyone know how I can fix this? Its really weird like my Z axis and my Y axis are both the yaw?
Here are 2 video’s which will explain my problem better:
i do have the exact same problem 
have you found a solution ?
Actually i just figured out that Roll value of root bone is already 90 degrees instead of 0. That’s why bone rotation isn’t working properly.
You probably used blender add-on and disabled rotation setting while adding a root bone to your animation. Try enabling those rotation settings and import it again. It worked for me and i hope it works for u too.
Thanks a lot for the hint, based on this I figured out the issue! Cheers! 
What was you’re solution? I’m having the same issue.
