I bought a brand new iPhone 6S on release. Used it as per normal, after about 2 weeks I noticed the Vibrate/Taptic stopped working randomly. So alerts/calls would not vibrate, nor would force-touch.
To fix this, I'd have to turn the phone off and then back on again. And it would resolve it, until it randomly stopped.
I went to Apple and the replaced the iPhone 6S for me on the spot. Great. I restored from my backup and used it, but then a few days in, BAM issue strikes again. Vibrate/Taptic stops working until I restart iPhone.
So I'm thinking it may be a iOS thing, so I Erase all Content & Settings off my iPhone. I then proceed to set it up as a Brand New iPhone. Thinking well now it's a brand new setup, surely this can't happen again.
No less than 24 hours since the reset the vibrate/taptic stopped working! I don't even know why anymore, one minute it vibrates when I get texts, next minute it doesn't!