Not sure if this is a bug or not, but the wife and I were riding tonight in stage 2 TOW and we were by ourselves. She had to coffee break to go to the washroom, so she latched on to me and I decided to step it up and go over 3.0w/kg. After about a minute or so, I passed another rider doing 1.8w/kg, and she slowed to their pace and I kept going not realizing. She came back before the timer ran out and and asked me why I was so far ahead.
Yesterday while I was riding solo I had someone zoom in out of nowhere with the coffee break icon and pace me. Once the started pedaling again they went back behind me by multiple seconds. My guess is coffee break latches on to the closest rider in front of you then resets to the previous distance from.