Will the 170k from the old chain be burned after today?
Of course coins will be burnt after today.
But the coins that will be burnt is not the 170k from the old chain as you are asking.
It is the remainder of the premine from the new chain which will be burnt because they werent swaped for.
But then some block explorers are on wrong chain?
And what are exchanges doing to be sure that theirs wallets are on the right chain and not on fork?
They can't be 100% sure, but what are they doing to reduce the chance to minimal level?