SO for a month now whenever I finish a rude my edge 1000 reports my average cadence which is typically around 90. Yet when I upload that number changes in garmin connect. For example today I rode with a cadence of 90, when I uploaded connect displays it at 76.
I'm getting similar problems with my 520. The head unit gives me what I believe to be the correct reading... but the imported data in Connect is significantly lower. Occasionally, there either a slight discrepancy with the max cadence figure, too.