Apple’s new iPhone X is already experiencing an issue that places a bright, green vertical line on either side of the device’s display. The issue has plagued a number of users who have taken to the internet to highlight the issue.

According to complaints from iPhone X owners impacted by the problem, the device is displaying a green line that spans the height of the device. The line has appeared the left side of the screen for some users and the right side for others.

The line doesn’t appear immediately upon booting up the iPhone X out of the box, but rather appears to develop over time. However in at least one case, the glitch developed rather quickly, resulting in the line appearing after just one day of use.

So far, users have aired their grievances over the iPhone X green line on Reddit, Twitter and Apple’s support forums, among other outlets.

“My iPhone X’s screen had a thin and bright green vertical line on the right edge before it completely blacked out and wouldn’t turn back on,” a Reddit user with the handle darlingvikki wrote. The iPhone owner reported connecting the device to iTunes and putting it in restore mode, which eventually turned the device back on but didn’t solve the green line issue.

Other users have also reported that standard fixes such as rebooting or performing a factory reset do not fix the issue, which appears to stem from the iPhone X’s OLED display—one of the primary selling points of the device.

There does not appear to be any particular indicator as to what may cause the problem. Users reported the issue on devices with different configurations for different carriers and in different regions.

Luckily for most iPhone X early adopters, the problem is unlikely to plague most devices. Thus far, the issue appears to be relatively limited and only a small percentage of device owners have been affected by the issue.

Apple appears to be addressing the problem head-on. The company is believed to be collecting data from affected devices to provide to engineers to determine what the cause of the sudden green line might be.

The company is also is replacing affected iPhones for free, according to MacRumors —though Apple has yet to publicly address the apparent issue or make clear its response to the problem for those affected by it.

Apple is not the first smartphone manufacturer to suffer from such a glitch. Owners of Samsung’s Galaxy S7 experienced a similar issue with a pink line appearing on the display of their device. Like the iPhone X, the Galaxy S7 used an OLED display. Samsung is also believed to be the primary supplier of the OLED screens used for the iPhone X.​