Read the citation you gave sensing the direct contradiction with the article and the 300M C (over 25KeV) is the reported peak (from the article, "up to" 300M C) while the "stable plasma" at an unspecified temperature was sustained for 70s.

The OP cites KSTAR as having the previous record but at a lower temp. It also says "100M C for 20 seconds" so I'm assuming the 70s number refers to a temperature graph that had some temperature but they had a bump that exceeded 100M C for a width of 20s in the overall time of 70s.