Macbook Pro 2016 Keyboard Problem

It's been reported by a number of users here. You might search the forums to see if a solution has been found beyond what I know. If it's a system problem then backup your files and work through the following:

A Troubleshooting Protocol to Identify Problems or Fix macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

1. Shutdown the computer, wait 30 seconds, restart the computer.
2. Disconnect all third-party peripherals.
3. Resetting your Mac’s PRAM and NVRAM
4. Reset the System Management Controller (SMC)
5. Start the computer in Safe Mode. Test in safe mode to see if the problem persists, then restart normally.
6. Use Apple Hardware Test to see if there is any hardware malfunction.
7. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
8. Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
9. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
10. Download and install the OS X El Capitan 10.11.6 Combo Update or 10.12.6 Combo Update or Download macOS High Sierra 10.13.3 Combo Update as needed.
11. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
12. Erase and Install OS X Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on Continue button.
2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
4. Set the Format type to APFS (for SSDs only) or Mac OS Extended (Journaled.)
5. Click on the Apply button, then wait for the Done button to activate and click on it.
6. Quit Disk Utility and return to the Utility Menu.
7. Select Reinstall OS X and click on the Continue button.

The space tolerance on the new notebook keyboards is so small that even a grain of dust in just the right spot can keep a key from operating properly. I've had quite a few students and faculty members bring me their notebook with problems much like yours. Sometimes I've been able to solve the issue with compressed air and a soft paint brush. Other times I've had to send them on the an Apple store. This new style keyboard is the #1 reason why I've not bought a new Apple notebook.

I am having similar problems with the keyboard on my MacBook - same vintage. It happened last year where it would double type certain letters. I took it into the apple store and they installed a whole new keyboard. Now it is doing similar things to what you describe, but on the space bar where if I don't hit the space bar just right, it won't put in a space. Or it will randomly throw in a period where one doesn;t belong.

I'm pretty sure it's a design/mechanical problem since this keyboard isn't a truly mechanical keyboard. It's sort of "semi-haptic" and in my opinion, it is not user friendly. I'm about to take it back to the store even though it's out of warranty, it's drving me nuts. I'd suggest you do the same. Love the computer, hate the keyboard.