I have created a new course and I have setup the expected average speed to 16km/h.
I have upload this course by using Garmin Express 7.16.3.0 (so far it is the lastest version).
When this course is received in the Garmin Edge Explore 2 with firmware 8.06 the average speed never is the same: Sometime is 0.1 Km/h sometimes is 36km/h.