My vivofit3 and forerunner 235 both sync activity tracking data but whichever I sync last overwrites the data for each day for the former. I don't wear them both at the same time. 235 is only warn to run and vivofit3 is warn all day as a watch. Vivofit3 wasn't syncing properly a few days ago and so updated the app. Still wasn't working so uninstalled and reinstalled.
Vivofit3 wouldn't pair with huawei p10 lite after reinstall of app as main device and since adding as 'not main device' now won't allow the switch to being main device within the app.