This is strongly indicative of an issue with the battery. From the use case of 15.3, we can see it is unlikely that a kernel upgrade included a regression that caused it.
Don't panic, yet... This doesn't mean that the battery is bad.
It may mean that the communication between the battery and the system is not working correctly.
Things you can try:
Remove the CMOS battery
If you have the setting in BIOS /EFI settings > Config for Disable Built-in Battery, select it
Hold the power button off for a good solid 30 seconds to drain capacitors.
Replace CMOS battery and reset in BIOS
Turn the notebook computer on and Do Not Charge. Use as normal until it is nearing death and then switch over to frivolous work or throw on an uninteresting video and let the notebook fully die.
Charge the notebook overnight.
The following day, power on the notebook and remove from charger. Use as normal until the battery dies again, then charge overnight again.
I realize that this is lengthy but... What this will do is recalibrate the battery sensor.
A possible cause: Not fully discharging a battery and then charging it repeatedly over a long period of time.
This is actually true for many devices, any OS or no OS at all... it includes rechargeable AA batteries, too.
Batteries are funny little animals and not as reliably centered as we would like to believe. Electron Exchange occurs in reality quite differently from how the Pop-Sci diagrams make it look in simplified form. And this can lead to artifacts.
By fully discharging capacitors and battery, you essentially give a known starting point: Zero.
Electron flow from Zero must then follow and maintain a path of least resistance.
Instead of electron flow starting at the last free movement, it now must start at the only available free movement at the bottom.
I realize that I laid this out rather poorly, but I hope it makes sense.
If the above does not work at all... Then you may have a dying or faulty battery.