NOVA 15": win update breaking changes for keyboard

If you haven't investigated the driver versions, look at the USB chipset and the device to see if you have the latest drivers.  Check for comments about problems with those chipsets and devices.  If you don't use external USB devices frequently, test with some external devices to verify that the USB controller is working reliably for everything except your keyboard.  You can at least rule out the USB controller hardware and driver that way.

More recent versions of Windows are more unpredictable about where they load DLLs and drivers in memory in order to thwart exploits for predictable software locations.  If you haven't done a rigorous test of the memory, I recommend doing that.  Faulty memory can cause all kinds of bizarre problems that make very little sense.

Check the thermal conditions of the CPU and memory to make sure that you aren't running into overheating.  If the CPU or other temperature sensors show overheating, then your keyboard electronics could be overheating.  You didn't say if this problem happens when the computer has been off for a long time and is at room temperature.  If it always happens when the computer is cooled off, or when it is very hot, then it could be a damaged component that works either at a lower temperature or a higher temperature.

Keyboards often have an internal micro-controller that provides the logic.  Verify if any keyboard functions work, such as special function keys, toggling indicator lights or manually controlled lighting effects.  If those functions work without the UEFI or BIOS firmware started up, but not when the keyboard fails, that points to the internal microcontroller of the keyboard.

If your battery is removable, try removing the battery as a fix before disconnecting the keyboard cable again.  Standby power can prevent some logic from being reset, and that might explain why unplugging the keyboard cable sometimes fixes the problem.  Completely removing power may reset the keyboard more completely than simply power cycling the laptop or rebooting the OS.

How old is the computer?  Is it possible that the coin sized CMOS battery is going bad?  That situation can cause uncertain firmware settings and intermittent problems.  Other signs of a failing battery are time of day that starts consistently behind the correct time after a period of being shut down.  You might not notice that if your computer automatically sets the time from the Internet.  You can either look at the BIOS, or the Windows event log to see what the time is on startup versus after running a while.  You will see the time correction where the time moves forward suddenly.

If you are not getting anywhere troubleshooting the problem, it's time to examine your assumptions about the problem to see if they are correct, and try some additional things to look for other possible causes.  We all want to be logical when troubleshooting, but some problems don't behave logically, and a logical approach can lead you in circles.

Depending on how much time you are spending on the problem it may be cost effective for you to just replace the keyboard, rather than trying to figure out that it is definitely bad.  The same may be true of the coin sized CMOS battery.  Those are often underneath the keyboard, or you have to remove the keyboard to change them.