Jim
doesnt matter. its is still happening. So, with that in mind, hats off to the developers for making the "Drivers" appear to react as real as possible, withot any input from the team manager. mightas well mark this one as "resolved".
Cars "offline" use kers randomly, at the beginning of the 3rd lap and every 7-8 laps since then. They also use it when you overtake them and a few laps have passed since the last time they used it. But if one of those cars just used kers and you overtake it, then it doesn't respond using kers again.
Also, if a manager joined the race and then goes offline, his car won't use kers again for the rest of the race.
That's just another one of the countless stupid things in this game. Nothing special.