This order is placed as stop loss market only, placed 2 lots, after it triggered at 149, order is sent as market and first lot is traded at 677 and seems there are no more counter orders pending and order turned into limit as when market order is placed when price is at circuits or no counter party it will sit in system as limit and hence it turned as limit, likely got LTP with price of 168 and got traded other lot at168, so one lot is traded at 677 and other at 168 bringing the avg to 422. Hope this helps but yeah this is a very rare case.