Thanks for the review, and welcome to the forum!
I haven't seen either of these issues on the Micras I've driven.
Issues: Brakes feel incredibly spongy and occasionally make odd sounds similar to a tuning fork. Transmission is clunky. Strange vibrations randomly occur when initially shifting into drive or revers with foot on brake.
Maybe worth a visit to the dealer?
View my fuel log 2015 Micra S manual: 5.0 L/100 km ... 56.5 mpg (Imp) ... 20.0 km/L ... 47.0 mpg (US) ...