Moved my Tab S2 to my wife, and got a Tab S3 when I upgraded my S8 to an S9+ phone. Been using it for three days. Used it this morning. No problems.
Turned it off for a few hours. When I booted it on, it asked for my security PIN. I provided it, and all I got for about 15 min was the open lock with the streamers circling it. Called tech support, and while on the phone with them it cycled back to asking for my PIN. Entered it, and it came on.
Long way to asking if there is a way to do a hard shutdown? On my phone, I believe, it's hold the volume switch and press the off/ on switch.