Apple is replacing iPhone Duo units that have developed screen defects days after the foldable phone launched at a starting price of £1,999 in the UK.

Users posted images on social media showing lines appearing across the inner display and cracks along the screen's central crease. Some owners also reported a crunching noise when opening the device. Apple said it was aware of "an issue impacting the inner display on a small number" of phones and told affected users to contact the company for a replacement.

One user, Justin Lokos, posted photos of a faulty device and thanked an Apple store in New York for providing a replacement handset.

The scope of the problem remains uncertain. Apple did not disclose how many devices were affected, and some images of faulty phones may have been created using AI, according to the BBC. Francisco Jeronimo, a technology analyst at IDC, cautioned that "some caution was needed before drawing conclusions about the whole production run."

The Duo's 7.6-inch inner display is engineered around a central hinge, a complex component that has produced similar flaws in foldables from Apple's competitors. Samsung's Galaxy Fold encountered broken screens during its 2019 launch when reviewers tested the devices.

Jeronimo said Apple faces "a steep learning curve in foldables" despite the company's engineering resources and supply chain capabilities. He added that because Apple positioned the Duo as a "premium alternative" to established foldables, "how it handles this first-generation issue will shape buyer confidence in the category well beyond its own sales."

Apple must clarify its warranty position quickly, Jeronimo said, as the Duo launches in 28 additional markets on October 30. Apple has a loyal customer base and retail network capable of replacing devices immediately, but clarity on coverage terms matters as the phone costs up to £3,199 for fully equipped models.

The Duo marks Apple's first major iPhone redesign in nearly two decades. When closed, it resembles a wide iPhone; when opened, it functions as a small tablet. New CEO John Ternus, who took over from Tim Cook in September, unveiled the device last month.