Motion blur rendering over objects

Hello, I got an issue with standard post-processing motion blur. I noticed that motion blur pass being rendered over previous objects' order. The chopper rotor being rotated with Rotate(value*Time.deltaTime) and I think that motion blur late with image processing due to high rotor speed. Is there any possible way to fix that?

Here is an issue with the video (time is 2:00).

 

The only way I know how to exclude something from Post processing is to draw it after the post processing is applied. Usually this is done with a two-camera set-up put the helicopter on a seperate layer and have a camera render only that layer, then the other camera renders the other layers afterward.

This might also be possible with render textures, but that would basically work the same way.