I got the 5X as replacement for a 3 (non HR). The 5X very often cannot reconnect to Garmin Connect after losing connection and coming back into its range. Meaning moving out of it‘s range and coming back into it it often will not connect and Sync even when forcing until I re-start the phone. I also tried switching BT on and off on the phone but doesn’t do the trick either. The 3 pretty much never had that issue. I am using an iP6s with iOS 11 and the 5X is on 6.0.
Anyone having the same issue? Any tips to resolve?