I have a bunch of problems with the iPhone app: Activities not uploading until after a restart, activities not being added to the weekly total, random restarts during long recordings, etc, etc.
Mine's been dodgy since iOS 9 upgrade (iPhone 4S though, so a bit outdated for the OS).
Most noticeable thing is that it doesn't show a weekly total. but does display everything it used to. My battery's knackered so I'm used to the thing turning itself off with '30%' remaining.
I have a bunch of problems with the iPhone app: Activities not uploading until after a restart, activities not being added to the weekly total, random restarts during long recordings, etc, etc.
Have you tried turning it off and on again?