When recording an indoor biking session on my Forerunner 955, Garmin Connect shows the speed graph as it should be within a range of 27 to 33 km/h filling out the whole graph.
However on the "last training" widget on the watch itself, it scales the graph all the way up to 240 km/h so that only the lower ten percent of the graph are used. The scaling seems way off here.
I've attached pictures for the same activity to illustrate the difference:
