I had a similar issue, although i could reproduce it and it almost happend everytime i watched through the Plex App.
Then i uninstalled the AMD Radeon Graphics Driver using their remove/cleanup (AMD)utility and downloaded the driver through AMD and not from the bundle. Its a different version i guess. The frequent freezes have gone away for now (2 Days).
It was my first and only delivery by FedEx. I wasn't at home so the delivery guy called me and asked if I knew a neighbor or if he should reroute it to my workplace. I took the second option and I got it the next day at work without a problem(Austria). But I guess u can always be unlucky no matter which delivery company.