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My iPhone 7+ keeps restarting for no reason is anyone else doing this

Not normal. Make a back up. Do a DFU restore as new and use it for couple of days with minimum apps installed. If the rebooting problem persists, it's hardware problem and you need to contact Apple.
 
There's another thread with people complaining about this issue as well, my phone has this same problem although it's a 7, I tried restoring, DFU, full reset and nothing, still randomly reboots, so I went to an Apple Store today and they ordered a replacement for me, hopefully that fixes the problem.
 
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