Just before the ball is punted, notice Summers himself was being held:
Right after the punt (left circle is ball leaving), see middle circle for Summers being pushed same as right hand circle the same for opposing player (they both end up on the ground after that), see circle on Summers his left hand, he may have been holding or pushing the guy down there hard to see:
Summers pushing through with hand on the guys helmet which is loose apparently and comes off, notice that the ref is not making any actions towards throwing the flag and the ball is long gone by that time.
Summers clearly being held while he has no contact going himself anymore, NOTICE THE REF REACHING FOR HIS FLAG in reaction to that:
Flag is thrown and in the air, the throwing of the flag is a direct progression from the motion started by the ref when Summers was pulled down (you see Summers tumbling forwards here as a result of that pull):
As far as I can see it, defensive holding after the ball was snapped could have been called (for pushing/pulling off the helmet) with the correct call being offsetting holding penalties but the holding prior to the ball being kicked call was plain wrong.