An unusual issue occurred at the Shanghai International Circuit, bringing out a red flag and disrupting a vital practice session for the teams.
The red flag caused a five-minute delay to proceedings, but it was not one of the cars that suffered an issue, it was the track itself, with the grass on the side of the circuit at turn seven catching on fire.
2016 champion Nico Rosberg speculated that a spark from one of the Formula 1 cars running in the only practice session of the weekend may have caused the fire, and marshals worked hard to extinguish it and get the session back underway.
It's the first time F1 has visited Shanghai since 2019 due to the COVID-19 pandemic, and a large amount of uncertainty remains about how the weekend will pan out, although a fire on the side of the track probably wasn't a factor teams prepared for.
Sky Sports F1 pundit Karun Chandhok described FP1 in China as 'the most important practice session of the season', with a lack of relevant data making it crucial for the teams to get some proper running in.
To make things even more unpredictable, the Chinese GP weekend marks the first sprint weekend of the season, meaning there is just one hour of practice before competitive action gets underway later on Friday with sprint qualifying.
That hour was eaten into by the bizarre fire, and the drivers were frantically trying to make up for it in the final stages of FP1.