Apple is looking into multiple reports of batteries swelling within new iPhone 8 Plus smartphones, which apparently broke them open as a result.

At least five separate reports of the new 5.5in iPhone 8 Plus smartphones have shown deformed phones, swelled batteries and screens being detached from the aluminum bodies of the devices.

The reports have spanned Hong Kong, Japan, Taiwan, Canada and Greece, all displaying similar symptoms, making the notion that there was simply a single bad batch of devices coming off the production line less likely.

An Apple spokesperson said the company was looking into the issues. Some of the devices were reportedly collected by mobile phone operator partners for investigation.

This is not the first time Apple has had batteries swell within new devices. The company manufactures and sells between 40m and 80m iPhones a quarter, a volume that means isolated issues are likely whether it be through manufacturing defects or problems during shipping.

But the spotlight has been shone on battery issues following the disastrous problems faced by Samsung with it’s 2016 Galaxy Note 7. Battery design and manufacturing issues led to Note 7s catching fire. The company recalled devices and shipped out a second batch with a different battery from another supplier, but it too suffered similar issues, leading to the company permanently recalling and discontinuing the smartphone, which cost Samsung billions.

The incident led Samsung and others to double down on battery safety and testing, with some winding back on more less proven developments and decreasing battery energy capacity to focus on proven technology and avoid a similar billion-pound catastrophe.

While swelling batteries is not nearly as bad as the cells catching fire, the chemistry of modern lithium-ion batteries and the amount of energy they can store makes them dangerous with any kind of fault.

Apple will hope that the incidents are isolated, can be dealt with swiftly and are not a prelude to further problems.