It could be just a normal part of driving. Checking my list of starting nomenclature I find: The egg shell start, The jack rabbit start, The blazing start, The slam bang start, The grinding start, etc.... and now we can add the "Jerk/Clank" start. Sorry, couldn't resist it.
Hope it does not recur and all is well.
2007 WK 3.0L CRD, Quadradrive II, GDE EcoTune, DPF-Delete
4xGuard Front, Rear, Belly, & Side Rails, Factory Skids
EHM MOD, Garmin Mechanic EcoHD, K&N Filter (Deleted)