XIAO_BLE_Sense(mbed 2.7.2) battery charge and voltage monitor, analogRead(P0_31) does not work

Hi There, So what is the final word on this in a nut shell?
I’m using the Arduino IDE ver 2.0.4. with hardware (mbed 2.9.1)
BLE & IMU & Sleep mode. All works but the stupid battery reading?
Varies , when it does work.
I just need a reliable report via the BLE of the voltage, or Level. BASIC shouldn’t be this wacky.
and why wouldn’t work on either mbed or not?
TIA
GL :slight_smile: