Just to say, that was a full throttle acceleration out of the pit! Tough to drive though while holding the camera, a replay did not indicate the stuttering motor as much at all.
I have used DLview to check if any other inputs were affecting it, throttle is smooooth and no dropping off at full. That was checked again today. Also checked again today was driving with the pedal app showing, as I did the other day though it wasn't on when I did the vid.
Todays session was the first I've had in a long time (of course) when I could not get this to happen no matter how I revved or downshifted hard. It was a thrill to be able to drive and push without having to fight this gremlin.
Having said that, I just drove again at another track and it happened again. I spun at a hairpin and had to get up for moment to "check" on the dogs, when I got back it happened after going back to the pit. Pedal app was on and there seems to be no problem with he pedal and again DLview looks good.
Did it again after restarting the session twice and after changing the track! Changed car to a GT2 and track no problem, back to the SF70 and problem instantly returned!
This has also happened with the 2004 Ferrari, the F138 and the SF15-t. I rarely drive the F1 cars and usually only the SF70h except as when an F1 event is being run and only doing setup and hotlaps. I have run in RD events using the Toyota and I cannot remember ever having a problem with it. I can never remember it being a problem with any of the other cars or ever when using ACC or AMS.