animated object flickering in the background

[thomes]

hello,
here a cropped part of two following frames of a fullhd mattecar/people animation.
animation is rendered with medium animation preset and animation prepass/rendering.

foreground is good, but in the background i have some cars and people that get "partly "black" for some frames...(here a car in the middle of the picture)

what do you think, too bad light solution ?
thanks for a hint.

thomes

[thomes]

high animation preset fixed it...