How to reproduce:
1. Open Unity
2. Load tester-submitted project(TimeLineRepro.zip)
3. Open 'TimelineSync.unity' scene
4. Play the scene
5. Open 'New Timeline' located in scene hierarchy in Timeline window
6. Play timeline and wait for sound while also looking when it should start

Expected result: Every clip in the timeline is played at the right time despite time scale
Actual result: Audio clip played early while sprite is enabled at the right time

Reproducible with - 2017.1.0b2, 2017.1.3f1, 2017.2.1p1, 2017.3.0p1, 2018.1.0b1
Could not test:
5.6.5f1 (Timeline is not included),
2017.1.0b1 (Audio is not played at all in the timeline)