I am just having trouble believing what I am seeing that's all. maybe the powder was wet or something and just puked it's way out the muzzle...
Phones are made out of some tough materials. I suspect that due to the angle of the strike, the phone slid across the pocket/shirt/body, thereby not causing skidding of the shot on the phone, but instead slid the phone across the victim’s body, spreading the impact energy across a larger area. And, as I think that you or another poster speculated, the victim may have been wearing a heavy (leather or other) jacket.
It isn’t that fast an expansion, apparently, and I’d bet the muzzle was close. Short barrels will at some point actually have a lower muzzle velocity because the projectile doesn’t have enough run in the barrel to take advantage of the expanding gasses from the burning propellant. Some of the powder charge is wasted as muzzle flash.