TMC4671 - Is it normal to have a current spike if PWM is enabled?

The current spike needs to be there and it doesn't affect the controller.

When PWM is enabled on the TMC4671, it has a duty cycle of 50%. This means it switches the voltage on every coil from GND to V_m and reverse. Every motor coil has a capacity to GND - this is only a few pF or even lower, but the hard switching results in a small current spike that's visible.

I=C\frac{du}{\differentialD t}

The du/dt can be reduced with output filters, something which is often done for EMI reduction.