Latitude 7490 keyboard issue

I suppose I'd try purchasing a replacement keyboard, and installing it myself. However, you have to be familiar with disassembly, disconnecting / reconnecting ribbon cables, have the proper screwdriver (use a magnet attached to the screwdriver, so the screws are easier to remove, and re-install.

Thank you. TBH I am not confident that keyboard replacement will necessarily fix the issue as I read many users in the past has similar issue with Latitude 7000 series and it might be a bios issue that Dell still could not solve despite updates.  Some user reported temporary fix w update but then problem reoccurring.  
My laptop is still within warranty.  I wonder whether Dell can replace or repair it for me.

Oh, then that changes things doesn't it?

I suppose I would try an experiment or two.

1). Go into BIOS and turn off C states. This will prevent the CPU from going into lower-power states. This should improve it's ability to respond to interrupts. Does the unit miss keyboard key-down events after doing this?

2). Go into Power Options, and see if keeping the CPU at a high clock rate prevents the unit from missing keyboard clicks.

3). Is the laptop connected to the internet when this happens? By hardwire or by WiFi? Try disconnecting from the internet, and see if the problem disappears. I ask this because maybe the unit is generating interrupts too often to support ethernet I/O over keyboard key-down interrupts... If this solves the issue, maybe there is an ethernet driver update you can install? 

Thank you.  do these suggested fixes address only the built in keyboard or any keyboard connected to laptop?  I know for sure external usb keyboard connected has no issue at all.  If it is indeed a bios issue, it somehow only affects built in keyboard firmware.
I contacted Dell support and they will send a refurbished keyboard for me to try replace.  not sure how technically difficult this may be.  I have only accessed memory and ssd on this model so far.

What I've provided you is some things to investigate to determine if the behavior is caused by keypress "interrupts" that might be missed because of something else going on - not necessarily bad keyboard hardware. I wouldn't call them "fixes".