I was watching Bosphorus today and the announcer made a comment about the match having 4 different countries represented (Turkey, Ukraine, Poland, Afghanistan). So that got me thinking, has there ever been an FRC match with all 6 robots from different countries?
I did find Qual match15 at Southern Cross 2018 had 5 countries (India, Vietnam, US, Taiwan, Australia), but my search was not exhaustive.
Southern Cross 2019 has teams from 9 different countries registered (out of 44 total) so it may happen there.