Single keypress types repeated characters (MacBook Pro 2016 & 2017)
Finally, if anyone had or has the same issue, Apple is replacing the keyboard free of charge / refunding the past repair : 
https://www.apple.com/support/keyboard-service-program-for-macbook-and-macbook-pro/

UPDATE. There is a small program, called Unshaky written on Swift. It fixed this issue for me.  It lets you configure a timeout for each key to suppress duplicate keypresses. For instance, if the 'e' key is giving you trouble, you can configure the timeout for a longer duration and adjust for the best results. There is also a statistics panel that shows how many times a key was suppressed by the software, as well as a detailed breakdown for each key.