According to South Korea's trade ministry
The ministry said that it notified WTO that it may suspend some concessions on tariffs on imported products from the US, after the tariffs implemented by the US earlier in the year on washing machines and solar panels here.
It also says that it will consider raising tariffs on some US products equivalent to $480 million - which is the amount Korean companies are expected to be handicapped because of the US' safeguard measures. The trade ministry says the timing and what products to be applied for the tariffs are to be decided later.
During bilateral talks - where they eventually signed a deal, the two countries failed to reach an agreement on this matter. Not too sure how well this will go down with Trump.