The reports began shortly after the foldable's September launch: users described the hinge tightening, after which opening the phone produced a crack and the distinctive bright lines. Apple spokesperson Alex Kirschner told The Verge that most units are not susceptible and that problems appear quickly on units with the defect. One user in Australia said an Apple Store replaced their unit on the spot.

There may be a mechanical explanation. iFixit, which published a teardown of the phone this weekend, suggests the foldable screen may be pushing against a centre bar where the damage has been occurring. The phone, launched in September as Apple's first foldable and the first marquee device under new CEO John Ternus, has been on the market for only weeks. The Verge notes it has contacted Apple but has not received an on-the-record response beyond the statement.