Hi...In my case DRV8825 set to 1/32 microstepping, driving dual Z motors in parallel.
After more searching online for similar issues, I read that its best to wire motors in series rather than parallel. So I made a wiring harness to accomplish this, and tested again, measuring the current. This made a significant improvement, but I still saw a jump from 0 to 0.22A or so which was not as smooth as it should . I wish I knew how to eliminate it entirely.