I tried to look up this phone, and different sources disagree on whether it has a single, 8 MP rear-facing camera, or dual 8 MP/2 MP rear cameras. There are clear pictures of versions with both setups. The 160 degree FOV suggests the image was taken with a secondary ultra-wide camera, possibly the 2 MP model. GSM Arena says the 2 MP camera isn't AF, which jibes with the EXIF reporting hyperfocal distance, rather than focusing distance, as it normally would with an AF camera. Of course, it's worth noting that EXIF data can just be plain wrong, I've seen it many times, especially with zoom lenses. Ultimately, though, I 100% agree that it's a picture of a monitor screen. That much was blatantly obvious just by looking at it.
tl;dr: the focal length calculation in the OP might disagree with the EXIF reported focal length because OP assumes the original image was 8 MP, when it could have been taken with a 2 MP secondary camera. Still a picture of a monitor, though.