PRIV touchscreen arbitrarily stops responding sometimes?
Starting last week, my BlackBerry PRIV has been having problems with its touchscreen. At one point, I picked it up to unlock it, and the screen was entirely unresponsive. Having experienced this issue happen once before within the first few months of owning my PRIV, I performed a factory reset using the AAL202 common autoloader from the official site (I have the BB-resold version instead of a carrier-based one). Unfortunately, that didn't fix it, and the problem has gradually been getting worse over the course of the last week.
The failure seems to be all-or-nothing. If the screen works when the phone starts up, touch works as expected, up until it stops responding altogether. I haven't had any problems with tracking on the screen, and the Virtual Expert tests found no problems. Sometimes the touch works with one swipe and then breaks on the next, and I've even had it break while drawing between the first and second points of my unlock pattern (the haptic feedback suddenly stops). The only way to get it to possibly recover is to restart the phone (holding down the power button for 1-2 minutes, since the 32-second hard reset doesn't seem to work either), and even that is extremely inconsistent. The phone isn't frozen, since I can still scroll with the keyboard and type normally if I'm in a text box; the touchscreen is the only thing that breaks. I've also had the phone randomly reset while I've been trying to use it, although only after the touchscreen breaks.
At this point, I've now factory reset my PRIV 6+ times via autoloader (the last time using AAL425 common instead of AAL202) with no change. Most of the time, the screen won't even work before Android boots (can't draw my pattern to continue the boot process), so I don't believe it's anything to do with apps. When I've changed my security to a password instead, I've been able to type it and start up Android even if the touchscreen isn't working, though that isn't terribly helpful since I can't really look at anything.
I most recently did a trusted reset to completely tear it down, and I've pulled the SD and SIM cards. Anyone have any tips on what else I might try? I get the feeling that the memory or something similar might be going bad, but I'm curious if there are any logs I could look at to narrow down root cause. I've had it for 16 months, so it's out of warranty now, and I haven't touched the firmware aside from these resets and standard system updates.