DRV8825: not enough current to drive stepper motor

Dear Support,

Here are my schematic design using DRV8825:

I faced strange behaviour as described below:

1. Good one show the peak current is at 1.64A

2. Faulty one, noticed peak current has halved, seems the output current is not enough to drive.  

OSC_Vref = 1.03V remain unchanged for good and bad IC. Likewise for osc_delay for both good and bad IC, it's at 1.63V.

Help needed:

1. Can you advice is capaciotr C67, C68 is necessary?

2. If I am using single step, the circuit will work.  but i faced some difficulty when using 1/2 or 1/4 step. 

3. how can i control and prevent the high inrush current and how tomake sure current limiting work? 

Hope to hear from you soon. 

Best Regards,

Felix