*Updated at 2PM: Sony is also aware of the overheating and/or temporary loss of camera functionality when using the Xperia Z2 to capture 4K videos. Here's the official statement:
Sony Mobile Singapore - "We are aware of some users encountering issues when shooting 4K video for extended periods. Shooting movies in high quality 4K resolution can make significant demands on your phone's processor and battery life, as well as phone memory. Therefore for the best experience, we recommend you install a high capacity SD card (Xperia Z2 can take a card up to 128GB) and shoot 4K video in short bursts of no longer than a few minutes at a time."
While HTC is facing SIM card issues on the One (M8), Sony is also handling problems of its own with the Xperia Z2.
Based on numerous feedback (1) (2) (3) (4) from the Sony Xperia Z2 user thread in HardwareZone Forums, the Xperia Z2 seems to have gap(s) between the front glass panel and the aluminum frame. The most commonly reported section is the top right corner of the device.
Apparently, the gaps are more obvious (and hence more widely reported) on the white Xperia Z2 than the black and purple models. Users expressed their concerns over dust accumulation at the gaps and whether the water resistance feature of the phone would be compromised.
We've reached out to Sony Mobile Singapore and they have issued an official statement:
Sony Mobile Singapore - "We are aware of some users’ concern on the waterproofing capability of the Xperia Z2 due to the presence of gap(s) and are currently looking into this issue. In the meantime, users who wish to [sic] may bring their Xperia Z2 to any service center to have our staff conduct a water resistant test.”
There are also other problems that users have reported, which include the camera overheating and shutting down during intensive photo-taking and video recording. We are still verifying these issues with Sony Mobile Singapore and will update this section when we have more information.