Automotive lenses and motion blur errors

[aTanguayII]

Seeing some rather odd behavior with lenses with motion blur on.

This is a very subtle movement of the camer, but the tail lights and the reverse lights have this very odd random noise going on.
The noise is different every frame.
Luckily the move is so subtle that I can live without it. But I need the option to be able to keep it.

Any clues as to what's happening here and what we can do about it? This is about 1600 samples, just for context. An HDR and one light inside the car. That's it.

[aTanguayII]

Any thoughts here? What's happening?

[npg]

The motion blur that we have is a quick post-processing pass, as opposed to raytraced. This is so that it can run in real time for our interactive mode. Raytracing the motion blur will make renders much slower. However the algorithm that we use is not perfect and sometimes generates artifacts.

Could you share a scene (even partial and very stripped down) that can be used to reproduce the issue?