Firstly, you haven't left the key in the in the car or a spare key in a hand bag etc.? This happens to prevent you locking the key on the car, but it will lock using the buttons on the key fob, because it knows you physically have it.
Secondly, when you mention the speedo, are you referring to the speedo showing 100kph while travelling at GPS 95kph? If so, this is meant to happen and it complies with Australian Design Rules(ADRs).
Link regarding ADR:
https://www.racq.com.au/cars-and-driving/safety-on-the-road/driving-safely/speedo-accuracy