the current taken from the power supply will be about 2/3 of the motor current you have set the driver to
unless you have an expensive meter from FLUKE that can read the complex current waveform
your meter will not be able to correctly display the current
the stepper motor current does not increase when the motor is stalled as its limited by the stepper driver
double check the motor connections -
with 8 wire motors if you wire a pair of coils so one coil is anti-phased the magnetic fields will cancel
normally when the voltage is applied to the coils the inductance limits the current
when the coils inductance is cancelled , the normal current control is lost ,
this results in excessive current in the coil and the drives protection circuit operating
John
PS
is this the wiring diagram you have used