On Garmin's, they have a setting to set whether or not you want to include or exclude zeroes from your cadence averaging. Does Wahoo have similar and have you set it up accordingly?

Be wary of any time you compare device data to what you see on a website. Websites may or may not show the accumulated data as the device does and will use other information from the data file to come up with their own idea of what you did. Many times they agree, but for some they don't.