Anyone seen a touchscreen fail by phantom clicks?

This morning my phone's touchscreen started going berserk. I have a developer mode setting enabled that shows a little bubble on the screen anywhere it registers a touch, and it's registering bursts of rapid-fire touches in a straight line across the screen (edit: always along the same line across the shorter dimension of the screen, it doesn't change), and it impressively but frighteningly acts on every single one of them. No amount of screen cleaning, rebooting, or even removing the screen protector has stopped it. Nothing changed or happened to the phone around the time when the problem started either. So I'm just curious if anyone has ever seen a touchscreen fail this way before, because I haven't - at least not without some immediately obvious physical damage.

I bought a spare screen for the phone early on, I was hoping to save it for replacing a cracked or burnt-out-looking screen but it seems I'll have to use it to replace this pristine-looking but glitchy one.

I have experienced laptop touchpads start doing soemthing similar when the batteries started to swell...

I've had it happen from moisture or debris stuck under the case where it met the glass. It didn't have to be near the phantom click spot. 
 

I've also had it happen from a battery pack that was getting bloated. 

No battery bloating issue here, it's a slider phone so the screen is separate from the phone body where the battery is. I haven't noticed any moisture or debris but I can't rule them out either. The problem seems to have slowed down since this morning but I don't think it's totally gone yet.

We had a very similar problem with one of the kids' Surface Pro 3s.   I'm pretty sure it's just due to age/usage (i.e., case being bent a smidge) causing a bit of pressure across the glass which in turn is causing a phantom touch with the capacitive touch screen.  This is the second one that's done it.

I don't think there's really a fix, but see if you can tell if the device has any bends you can see, and apply pressure to bend it straight.  It might work, it did for one of the surface pro 3s... The other one I just had to disable the touchscreen, which is a lot more useful of a fix on a computer than a phone :)

The touchscreen is technically two discrete elements: the display and the digitizer. These are akin to you computer monitor and mouse, although in most touchscreen devices one is layered over the other. Either one can fail on its own, and what you are describing is classic digitizer failure.

I have witnessed this personally on several devices (one iOS, multiple Android) that were dropped; the display and case showed no appreciable damage, but the damaged digitizer began registering phantom taps and tap-and-holds.

For what it's worth, you can hook up an external pointing device (bluetooth mouse, or even wired with an OTG cable/adapter) in case you need to rescue any data or account info.

The straightness of the device has looked a bit questionable pretty much as long as I can remember, checking it with a ruler confirms a significant but symmetrical arch to the main body, the screen looks close to perfect with maybe a slight outward bowing.

The phone started suffering nonstop grand mal touchscreen seizures tonight so I had to take it into emergency phone surgery, operation was a success, oddly the replacement screen doesn't have any touch sensitivity on the curved screen edges, it's enough that I can't get to the ConnectBot lower controls and can barely get to text fields at the bottom of the screen in landscape mode, but at least the phone is usable again...

Glad you got it, well, kinda sorted out.... 

Yeah, I've had a <50% success rate on replacing screens and being happy with the outcome.  I don't think the quality of replacement hardware is really able to be discerned ahead of time. 

For the most part, if it's a kids device, I'll go for it, but if it's a daily driver, my wife and I interact with it too much to suffer annoyances (there's already enough of those in modern OS designs!).

It's a thing that occasionally happens on iPhones. Saw it the other day on an XS. Could replaced the screen I guess...

I had a laptop touch screen start doing that. I was able to turn off the touch function. Since I never used it it wasn't an issue. Kind of hard to do with a phone though. 

Update: Was browsing around on the user forum for this phone and ran into other people with the problem of no touch sensitivity near the edges after installing a 3rd-party replacement screen, I was able to fix it by reflashing the screen(!) with some sketchy Chinese software!