A number of Samsung users on the Samsung forums are complaining of their Galaxy Note 8 devices freezing up and becoming unresponsive. The problem seems to be affecting devices across markets, including the dual SIM versions. The only way to recover functionality on the phone is to restart the device. The problem persists even after users clear the cache, reinstall applications or perform a factory reset.
A number of posts point to the freezing occurring while using the contacts app, leading to speculation that there may be a conflict between Samsung's contacts app and the one that comes with Android. Users have pointed out that opening the contacts app freezes the phone, but it is possible to make a call through the numeric keypad. The freezes are triggered while using certain apps including Google Chrome or the Google app. Android Police has put up a list of known instances that trigger the freezing.
Apart from the freezing up issue, users are also reporting that the phone just restarts on its own while using some apps. The freezing and restarting is pretty frequent, and many users have pointed out that they have to restart the device multiple times in a week. Hopefully, this is likely a software bug that Samsung can fix with an update.