Blue light means Artemis has a penalty. How did that happen? Green light means they are in the three boat length zone at the gate. (Explanation of lights here.)
As they approach the three boat length zone at the mark, you can see Artemis’s bow, just about to enter the zone. Team Japan is overlapped with New Zealand, who are overlapped with Artemis. Rule 18 gives both NZL and JPN rights to round the mark inside Artemis.
JPN has gybed and gone behind NZL, and they still have rights to round inside SWE.
NZL escaped the mess at the mark. SWE has been penalized for not giving JPN room. Meanwhile Land Rover BAR has stayed out of the fray and now has enough speed to round outside. Artemis was in third place as they approached the mark but finished the race last. Ouch!