You can double check you preferences
>system preferences>Keyboard also
>system preferences>Accessability>Keyboard and see if there is something there for a resolve
2016 and 2017 have a service program for keyboard issues, not for the 2018 however
https://www.apple.com/support/keyboard-service-program-for-macbook-and-macbook-pro/
I would not hesitate to take it in for a over the counter assessment, If for no other reason a service record is generated for your Mac, documenting the issue.
In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test
Make an appointment for a hardware issue—
https://www.apple.com/retail/geniusbar/
https://checkcoverage.apple.com/
https://support.apple.com/my-support
https://support.apple.com/en-lamr/aasp-program
From iOS online Genius Bar appointment:
https://itunes.apple.com/us/app/apple-support/id1130498044?mt=8