hello ! white smoke occours when fuel is injected into a still hot chamber but ignition is forgotten or the igniters failed . first it evaporated only in the hot chamber without burning then excessive fuel finally self ignited against the hot chamber or you turned ignition on after introducing fuel via condition lever making it ignite . the excessive fuel suddenly igniting resulted in the high itt .
you most probably forgot to turn on ignition on first start attempt .
good news : your engine is fine , 1000 deg for a short time is a non event.
generally on quick turnarounds motoring for 10-15 sec before pushing the condition lever helps much lowering peak start temperatures.
best regards