Matinee - Camera never leaves postprocess volume

I’ve created a scene which I want to capture on video using Matinee. The camera has to float through a tunel to the open space. I’ve set a short postprocess volume at the end of the tunel, so the camera should float through it and right after that should leave it.

But… when I record the sequence, camera enters volume, postprocess launches properly and then …it lasts forever.
What’s going on here?

Also, why the performance during matinee is much worse than in the engine in play mode? oO