George Russell experienced a Mercedes Formula 1 engine software issue at the Hungarian Grand Prix grid, causing his revs to go out of control and triggering a slow start. This followed a water leak from hitting a kerb that destroyed his engine, necessitating a change before the race.

On the grid, the anti-stall was activated due to a technical problem beyond the driver's control. Toto Wolff explained that the engine revved excessively, causing Russell to lift off the throttle, which then led to a rev drop. This sequence of events, not a driver error, resulted in Russell starting with less throttle input than his teammate Kimi Antonelli.

Telemetry confirmed the engine's unstable revs, peaking at 12800rpm and dropping significantly when Russell attempted to modulate the throttle. This led to the engine triggering anti-stall and compromising Russell's race. The team had encountered a similar issue during pre-season testing in Bahrain.