In my notes I have the Injector Nozzle Nut to Injector body torque as 54 foot pounds.

When you pull the Injector out take a close look at the Nozzle Nut for hairline cracks. I does not happen often but some times the crack.
Another possibility is that the high pressure Fuel has eroded its way through the inside of the Injector where the parts mate; but this is extremely rare.

If it is really spraying out a lot of fuel I woud suspect a cracked Injector Nut or some other problem the just re-tightening it will not help. However, it cannot hurt to re-tighten it.
Re-tightening it will retun it to the pop pressure it was set at before it was loose.

__________________
84 300D, 82 Volvo 244Gl Diesel