TMS320F280025: ACIM - FWC only in one direction

Tool/software:

Hi,

I'm using the MotorControl SDK V5.0.2 with the universal motor control example with a ACIM motor. Now it seems to work fine, expect there is a problem with FWC. 

FWC seems only to work in the positive speed direction and it increases the magnetic current in the opposite direciton. Is this a bug? When I do the following, it works,

but I'm not sure if MTPA then still work:

in motor1_drive.c (use fabsf of IsRef instead of directly IsRef seems to solve the issue):

Thanks