Apple has been blamed for failing to address a design issue with the iPhone 6 and iPhone 6 Plus which causes the screen to flicker and become unresponsive.
According to repair specialists at iFixit, "a ton" of iPhone 6 Plus handsets have experienced the problem, which it has called "touch disease."
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The company also claims that a smaller number of iPhone 6 handsets are also affected.
"Every repair tech we spoke to told us that the problem is incredibly common," iFixit said.
The problem, it is claimed, is that two chips on the logic board work their way loose from the soldering as the iPhone bends and flexes slightly during use (so in some ways this problem is related to the Bendgate issue where iPhones were breaking in user's pockets). Initially the problem shows up as an intermittently unresponsive touch display, but over time problem becomes worse until the touch screen is completely unusable.
Fortunately, there is a fix.
If you handset is under warranty, then the good news is that Apple will sort you out. If it's out of warranty, then Apple will either sell you a replacement logic board, or a new iPhone.
There are specialist third-party repairers who can fix the problem by replacing the two affected chips on the logic board.
It's hard to tell how widespread this problem actually is. While I've not seen the problem myself, I have come across reports of it previously, and some of the third-party repairers interviewed by iFixit sounds as though they are inundated by requests to fix this problem.
Whether it is widespread or not, Apple could do without being at the center of a possible iPhone design bug, especially at a time when iPhone sales are weakening.