Some buyers of Apple’s first foldable phone, the iPhone Duo, have reported inner-screen cracks and bright lines along the fold within hours of last week’s launch, and a teardown by repair site iFixit points to the hinge as a possible mechanical cause^1,2,4,7.

Apple told CNBC it is aware of an issue affecting the inner display on a small number of units and that owners should contact AppleCare for a replacement⁷. The company also said early user response has been positive and that developers are updating apps for the form factor⁷.

iFixit built a 3D hinge model from teardown footage, patents and CT scans and compared it with reported damage sites¹. In one closing simulation, a center support bar failed to drop far enough, so the screen’s curved fold came down onto it and created a stress hotspot near where breaks cluster¹.

Those breaks cluster near the transition from a gap for a crossing flex cable to the central hinge support, slightly below where the display cable passes through, at a point where several edges meet⁴. Ars Technica reported that some owners feel unusual resistance or hear a click as the device closes, after which lines appear⁴.

The Verge quoted iFixit technician Shahram Mokhtari saying that at the troublesome spot the flexible inner screen can push against part of the hinge, and that photos often show a black spot where metal may hit the panel². CNBC quoted him saying, “Right where the damage is happening, the hinge is shaped a little differently”⁷.

iFixit also found that fine particles can reach the moving hinge even though the phone carries an IP68 rating for the enclosure, and that dust made the hinge crunch in a powder test¹. The site gave the Duo a provisional 5 out of 10 for repairability, its highest foldable score so far, while noting inner-display replacement is listed at $999 without coverage^1,6,7.

BBC reported Apple will replace affected handsets and that the UK starting price is £1,999¹⁰. The Guardian reported owner complaints of cracks alongside Apple’s small-number claim⁹. 404 Media collected social posts describing creases, cracks and a crunch while opening, and noted that a visible crease is also common on other foldables⁸.

The scale of the failures is not public. Apple has not announced a recall². Mokhtari told The Verge that if the same failure is still appearing months later it could indicate a wider problem². How many units are affected, whether the cause is manufacturing variance, debris or design, and whether later production will change remain unknown^2,7.