I am having an odd issue today - I synced my vivofit via my Garmin Connect app on my iPhone6, and it all updated fine except for my Activity, which still shows Monday's date and activity.
I was watching my heart rate on my vivofit constantly last night, due to frequent disconnects prior to me replacing the battery, and heart rate was registering fine - no dropouts at all. Yet today it's as though there was no data collected from the 2 hours spent at the gym!
All 9000+ steps registered normally...