It was already a bit to come, but the second engine of Sergio Perez and Max Verstappen can no longer be used. Honda has confirmed this today.
Erik van Hagen reports that the Silverstone engine of Verstappen has been tested but is not usable anymore. This means that Verstappen is definitively stuck with his third engine, which was used during the Hungarian Grand Prix.
Perez cannot use his second engine either.
This leaves Red Bull with a big problem. Each season teams are allowed to use three power units and replace two without incurring a grid penalty. With twelve races to go and both Perez and Verstappen already on three, the next engine change will move both drivers backwards on the grid.
Normally with so many races to go, there seems to be no escape from that. Red Bull will now have to decide when is the best time to take a grid penalty. This could be during a race weekend at a track where the Red Bull is not that fast or Verstappen doesn't finish qualifying or starts further down the grid anyway.