Well it's odd because a sentence later it is being emphasized that the water must be 190 not 189 or 191. Maybe the kettle was set to 220 as some strange setting not relating to the actual temperature of the water? Or maybe being NBA players they have a moon kettle.
It seems most likely to me that is a typo that slipped through the editing process for the article.
Aren't espresso machines pressurized?
Earlier in the article it mentions an electric kettle and a french press. My guess is the reliability of a thermometer on an electric kettle (especially one that travels that much) is suspect to begin with, and might read 8F high.