Zbook 17 Mobile Workstation locks when unplugging, then not booting on battery
Product: Zbook 17 Mobile Workstation
Operating System: Microsoft Windows 10 (64-bit)
My Zbook 17 Mobile Workstation is having problems when unplugging the AC adapter. The problem is that when unplugging the AC the Zbook automatically locks (suddenly black screen, it seems like the battery is immediately unplugged). Even when the battery percentage shows 74% for example (or maybe even more).
After the laptop goes to black screen, the Zbook can not be started on battery (so without the AC plugged in), but does boot again when AC is plugged in. The laptop even shows the same windows/programs still open so this means the laptop doens't completey shuts down but it 'locks'.
In the beginning (A few months ago) I had problems with charging, Zbook didn't charge completely and stopped charging at around 47%), so what I did was replacing the AC and the battery with new original components.
Also after I bought these original AC and battery, I did a hard reset by following the recommended steps for a hard reset and I even calibrated the battery. HP support assistant tests are showing no hardware problems at all.
Things I already tried:
installed all the latest updates
bought a brand new AC and battery compatible for Zbook 17
Deleted and reistalled all drivers for AC and battery
Hard reset (as recommended by HP) > this seems to work for a while, battery is charging till 100% but when unplugging after about 15 minutes the Zbook still randomly locks and seems to go to sleep(?) (because programs are still open). But most important thing to know is that Zbook doesn't boot when AC unplugged, even when battery is fully charged.
Does this sound familiar to anyone and any solution on how to solve this?
My guess is that, it has something to do with the software. But not sure where to look.