Timeline stops playing after adding new cinemachine track

I added several Cinemachine Tracks and Virtual Camera’s to a new timeline. All transitions on the timeline worked fine. Then I added a new Cinemachine Track, and now the timeline won’t play anymore (playmode AND preview mode). Has anybody encounters this? When I open another scene with a timeline, the timeline there is just working fine.

Turned out another track had a character animation on it that wasn’t working. That caused the whole timeline stopped playing. I found out by muting all tracks and un-muting them one by one.

In my case, I juste update Unity to 2017.2.0b9.
The bug seems to be corrected.