Have Garmin Index Scale. I do a weigh in, it syncs via WiFi, I check Garmin Connect Mobile, I see the correct weight; but, some time later I check Garmin Connect and it has the day before weight for today and Garmin Connect Mobile has updated to show the day before weight, as well.
Also, Garmin Connect does not push or sync weight with MyFitnessPal unless I manually input it via Garmin Connect.
So, somewhere between the Index Scale, Garmin Connect, Garmin Connect Mobile and MyFitnessPal something ain't right and I believe it's Garmin Connect. The end result is any attempt at tracking weight data through Garmin Connect is useless.
Note I've disconnected and reconnected MyFitnessPal and that didn't resolve syncing weight data registered by the Index Scale.