Looking at the arrivals it looks like it is the Karachi flight despite reports saying the flight was inbound from Turkey.
AirBlue fly Manchester-Islamabad with a fuel stop in Trabzon (allegedly the world's longest A321 route), maybe that's where the confusion has crept in.
How that fits in with a KHI-ISB flight I don't know, although I see that the downed Airbus is now being reported as one of their A321s.