The first week or so that I had the device, a couple times the upper left hand corner stopped responding to touch, but a reboot resolved it. I have had the come back (knock on wood) since.
I find it does this only when I have the keyboard out and a finger on it. Probably because its;s touch sensitive and I'm touching it at the time. Otherwise no other issues.
My touch keyboard has frozen on a few occasions. Rebooting didn't help. Physical keyboard kept working. Notification screen kept coming down too. Seemed to happen when battery about 30%. Didn't notice if linked to any particular app. Been OK for a few days.