i am using a makehuman character with mhxrig and retarget it with a .bvh file…but not acting as desired…how to fix it ? 
Get rid of the mhxrig and just use the bvh rig.
Align the bvh rig to your mesh and parent it then go Pose–>apply pose as rest"
this action will break the bvh animation so you will need to import second copy of the same bvh rig and then re-target.
Oh IMPORTANT!!!..after retargeting, if the 2 rigs are not standing in the same spot you will need to select the hip bone go to the constraint panel and add a “location” constraint.
Tip: don’t use rigs with constraints when re-targeting. use very basic rigs with no constraints.
thank you ! 