this may be what happened dave,
when you cranked the car th first time the injectors were opening but there was no spark while cranking and hence all the cylinders and exhaust filled up with fuel.
the second time you only turned the ignition on the there was a flame show.now as far as i can recall the p8 ecu and maybe the l8 as well give the coil trigger an initial blip with the ignition only switched on and this causes the coil to fire and spark the plug nearest the rotar if at all, (it may be just an ecu self test?)
now because you running a coil pack i think it works on the wasted spark system where more than 1 plug fires at once (i think its 2) and so by your defo going to get a spark in one or more cyls and if the exhaust valves ore open you will get flames.
what you may have is the initial spark with ignition on and none when cranking.
you could try by disconnecting the injectors to stop more fuel going in,then pull out the plug leads and put a spark plug in each one and earth them all.then turn on the ignition and see if you get a spark on any or all of them.then crank the engine and check for all of them to spark
if they are its possible you have a timming problem,if not then you have a triggering problem
hope this is of some help and not full of errors