Apple may have found a way to make the crease on its first foldable iPhone almost invisible, but a new video suggests the iPhone Duo’s display still has a noticeable weak spot around the hinge.

The footage, originally shared on Weibo by user Kang and later reposted by Ice Universe, shows the inner display slightly depressing when pressure is applied to the area directly above the hinge.

While the screen appears smooth under normal use, pressing down on that section reveals that it doesn’t have the same firm support as the rest of the panel.

According to Kang, applying pressure can also cause temporary wrinkles to appear on the display’s surface. These reportedly disappear once the finger moves away, although the behaviour raises questions about how well the screen might hold up after months or years of regular folding and use.

Kang also claims to have tested multiple iPhone Duo units, all of which showed the same response, suggesting it isn’t an isolated issue with a single device.

One possible explanation is Apple’s rumoured use of variable thickness glass, which is designed to make foldable displays more flexible without sacrificing durability across the entire screen. Ice Universe suggests this could explain why the hinge area feels softer, although Apple hasn’t confirmed whether the iPhone Duo uses the technology.

Corning previously demonstrated a similar approach with its variable thickness glass (VtG), which uses a thinner section over the hinge to allow the display to bend more easily, while keeping the surrounding glass thicker for added strength.

If Apple has adopted a comparable design, the softer area could simply be a consequence of making the crease less visible rather than a manufacturing defect.

The iPhone Duo’s inner screen protector is also reportedly replaceable, which could make surface-related issues easier to address. However, there’s currently no evidence that the temporary wrinkles shown in the video will lead to permanent damage.

For now, the footage highlights a potential trade-off in Apple’s approach to foldable displays. The company may have managed to hide the crease from view, but whether that design can withstand long-term use remains to be seen.