I can imagine PERFECTLY HOW THIS PROBLEM FEELS LIKE. After having the same issue with my macbook 2011 bought in 2016 I gave it to app store and they changed the WHOLE keyboard system for free! Guess what? After 5 monthis this started happening again!!! I was able to solve this problem by turning the computer over and starting hitting some areas. I think its not the problem with the system but with the connection between parts of the computer itself. NVRAM is not possible to reset simply because keyboard doesn't respond. I can't explain with words what I have been through with this ***** problem...