Cubase 8.5: Automation Bug? Faulty event reduction.

Following issue. Screen capture video is attached.

  1. Automation event reduction factor is set to 50%.
  2. After automating a track the reduction factor is NOT applied.
  3. After automating another track the reduction factor IS applied.

I could not detect any reason why some automation data are even-reduced and other are not.
I could not find any way to reduce the event-density of the over-automated tracks afterwards.
The manual mentions a function for automation event reduction (page 618), but this
function does not exist.

This is quite ennervating. Same issues anyone?
New insights after some investigation:
The automation reduction factor is NOT applied if the track is linked to a VCA fader group.
As soon as I break the link the reduction factor is applied correctly. Seems like a bug.