We are currently aware of various issues regarding the Sleep chart and data not displaying correctly (or at all) after syncing the Vivofit with Garmin Connect Mobile. In some instances, the chart data would only display after users "confirm" their sleep time or after they sync the Vivofit with Garmin Connect Web rather than the app. In other instances, the chart data never displays regardless of what the user does.
We are expecting a fix to these and various other issues to be released with the next major Garmin Connect Mobile app update, which should be released within the next month or so (pending no interruptions or delays). We apologize for any inconvenience that this may have caused.