Some buyers of Apple's iPhone X are encountering green lines along the left or right side of the OLED display, according to various accounts on social media.
The lines appear to be developing after use, in at least one case just the space of a day. Complaints have arisen on Reddit, Twitter, Apple's support forums and elsewhere.
Restarting or restoring a device doesn't fix the problem. Only a minority of people are believed to be affected though, regardless of a phone's configuration or the region where it was bought.
Apple is replacing affected iPhones for free, MacRumors indicated. At the same time it's thought to be collecting data for engineers with the hope of diagnosing the issue.
A similar glitch once affected the OLED screen on Samsung's Galaxy S7. Indeed Samsung is thought to be the lone OLED supplier for the iPhone X, as the only company with enough manufacturing capacity to meet Apple demands.