Steps to reproduce:
1. Download attached project
2. Open "SampleScene" scene
3. Open Animation from Timeline
4. Enter play mode
5. Check Console window

Expected results: Animations event triggers once in the animation loop
Actual results: Animation event triggers twice in the animation loop. Once at animation event and other time at the start of the animation loop.

Reproduced with: 2019.3.0a11, 2019.2.0f1, 2019.1.13f1, 2018.4.5f1, 2017.4.30f1

Note:
- Not reproducible when animation with an event is used in without a Timeline.