Apple’s first foldable iPhone is facing renewed scrutiny after owners reported cracked internal displays, with some claiming replacement handsets have developed identical faults within days.

The iPhone Duo, which starts at A$3,499 in Australia, has been on sale for just over three weeks, but concerns about the durability of its folding screen continue to mount.

Apple previously acknowledged reports of damaged displays and began replacing affected devices, although fresh complaints suggest the problem may not have been fully resolved.

One Reddit user claims their replacement iPhone Duo developed the same defect as their original handset less than 24 hours after receiving it.

Both devices reportedly suffered damage in the bottom-right corner of the folding display, with a vertical line of dead pixels and visible bubbling along the crease.

The owner said they had taken extra precautions with the replacement, including cleaning the screen before folding it and ensuring no debris was trapped between the two halves.

Another customer reported having their original iPhone Duo replaced after noticing a raised section near the hinge.

However, the replacement’s internal display allegedly failed just three days later while the phone was being unfolded.

Although the external screen remained functional, the owner said they were considering requesting a refund and switching to an iPhone 18 Pro Max.

Other reports indicate that failures are not necessarily confined to the first few days of ownership.

One launch-day buyer claimed their device developed a crack after almost three weeks of trouble-free operation, while another reported a white line appearing across the internal display after a similar period.

The latest complaints follow earlier reports of cracks developing around the iPhone Duo’s hinge shortly after its launch.

Apple subsequently acknowledged the issue and advised affected customers to contact AppleCare, maintaining that only a small number of devices were involved.

However, the emergence of similar faults in replacement handsets raises questions about whether the problem extends beyond an isolated production batch.

Previous teardowns have highlighted potential concerns with the hinge assembly, including the possibility that pressure from the mechanism could damage the flexible display.

Neither investigation established a definitive cause, and it remains unclear whether the failures are linked to the hinge, defective display components or manufacturing inconsistencies.

There is also no reliable information indicating how many iPhone Duo devices have been affected, with numerous owners reporting no issues.

Apple’s customer support response has attracted some positive feedback, with affected users reporting straightforward replacements and, in one case, an upgrade to a higher-storage model.

However, replacing damaged devices may not fully address consumer concerns if the same faults continue to appear.

Apple has not confirmed whether changes have been made to newer production units to prevent further failures.

For a smartphone costing upwards of A$3,499, ongoing uncertainty surrounding the durability of its most important component could become a significant obstacle as Apple attempts to establish itself in the competitive foldable market.