The current taken by a brushless motor may be very variable (a series of pulses), so this may be accurate even though you think its not. The Multimeter will be adding resistance into the circuit, changing the behaviour.
But first please post your circuit as this matters. Perhaps you've not connected the bandwidth select pin, perhaps you've neglected decoupling or the output filter capacitor is too small - all such issues are immediately apparent if you post your circuit - hand-drawn is fine.