Kor Blademaster

• WOTC Official Reminder Textofficial rules
  Double strike — This creature deals both first strike and regular combat damage.

• WWizards of the Coast2020-09-25
  Official Ruling
  If a creature loses double strike after assigning damage in the first strike combat damage step (due to Kor Blademaster leaving the battlefield, for example), that creature won’t assign damage in the normal combat damage step.

Rulings via Scryfall