That gets me thinking about some "tests" I could do.
I actually had a similar situation to the above except, maybe a little less R rated. The last two days I have been riding the bike trainer indoors. I'll put my Garmin on to track time and heart rate. Well, for some reason it finds a satellite even though I am indoors so the map and distance end up a little... Wonky. I usually override the distance based on time, but generally speaking the watch will say that I go about 0.15 miles per hour.
SOMETHING was going on while I was on the trainer!
When you have friends like this, who needs enemies? Happy Friday!