Issues with velocity setting

Recently, I tried to build coreXY with Odrive. So I need to set different velocities for each motor to make sure two motors start/end at the same time. I used set_vel_setpoint( ,) to realize this. But the velocity (counts/s) shown in command .encoder.pll_vel seems not to be the value in the .set_vel_setpoint( ,). I also played with the .vel_gain but it didnt help too much. Besides, when I use .set_vel_setpoint( ,), motor seems lose lots of torque. Can anyone give me a hint for changing motor velocity correctly? The following are the original parameters i used in the low_level.c.

Thanks in advance,

What numbers do you put for the parameters of set_vel_setpoint( ,)? Did you put any non-zero value for the current feed_forward? Maybe try writing to vel_setpoint property directly?