Bought the Pi 7" touchscreen just before Christmas with the view to playing with it over Christmas hols. However, the touch part didn't work well. After booting Raspian, it would work for a few minutes, and then start picking up some spurious touches, mostly in the same area of the screen. This would get pregesssively worse until it is actually not registering genuine touches at all. If left for a long time, it would sometimes recover, but then also sometimes go back into broken mode. A reboot mostly seems to start the process over again with it working initially, and gradually becoming unusable again (which is strange, as it felt more like a hardware fault until I discovered this).
Anyway, got bored, and put it back in the box for another time.
Another time came last week, and I tried again, having updated the OS to the latest (apt-get update; apt-get upgrade). No different from before. Tried disconnecting and reconnecting the thin touchscreen cable connector on the PCB, but no different.
I only found one other description of this behaviour in an unanswered question on a forum, so I guess it's not very typical?
Is there anything else I should try before sending it back as faulty?