It's something I'll look into when it happens as I do my current play-through - its hard to force and thus, test a VSC extensively so I'll look at is as and when it comes up.
Looking at the pictures, the entire field bunched up by about 15seconds total - so I wonder if different cars are put under the VSC at different rates, I.e., those closest to the accident are notified first like yellow flag behaviour? Or maybe its because of "car AI scan". You see, cars don't continuously process their strategies - that would be a lot of processing. So they only adjust their push/fuel/pit behavour when they hit a refresh timer. - Maybe they don't obey the VSC until the refresh its.
Anyway, it's not something I'll get to work on, but I will be on the lookout to see if I can work out whats going on when I see it.