Current consumption of EM2 is expected to be several uA in the current measurement by Energy Profiler, but it has been confirmed that it is almost zero.

There is a known bug in the control part of AEM (power monitoring module) in the starter kit that supports mbed, and this is the effect. I don't think there is a big problem in observing the transition of power changes, but it is inconvenient when you want to make quantitative measurements.
As an interim measure until the manufacturer supports it, you can solve the problem by downgrading the control firmware of the starter kit and making it unsupported by mbed.

Please refer to another topic for how to return the starter kit to not support mbed.