Motorola smartphone released June 2016 with additional features called Moto Mods (Speakers, chargers, etc). At the time of its release, the Moto Z was the thinnest smartphone ever (5.2mm). Model numbers XT1650-01 and XT1650-03.
Try using the phone in safe mode and see if the problem still occurs.
If it doesn’t occur in safe mode (allow enough time to be sure) and it is operating on the battery only, then a downloaded app is the problem. The trick is to find out which one. You’ll need to uninstall each downloaded app, one by one, and run the phone in normal mode between each uninstall to see if it operates correctly. Once it does then the last downloaded app that was uninstalled is the cause.
If it still occurs in safe mode and if it only has problems when working on the battery only, then perhaps the battery is failing and needs to be replaced.
Replacement batteries are available online. Just search for Moto Z battery to get results for suppliers of the part. Ensure that it is suitable for your exact model number.
Yes. It seems as though the battery is the problem.
If it were another hardware fault or a software problem which was causing this to happen normally it wouldn't matter whether you are on battery power or charger power, it would still happen
Interestingly, coincidentally I thought this was my problem with my Moto-Z Play restarting/rebooting… in fact, it was the aftermarket case that had either aged/hardened (soft rubber extrusions to volume/power buttons) or just shrunk/tightened and it was the physical contact with the case that was restarting the phone. Simple in the end but frustrating to trouble-shoot. Thought this might help someone else with the…not so obvious.