To reproduce:

1. Open the project, attached by tester (TimelineBug.zip)
2. Open "main" scene if not open
3. Select Bakkal object in the Hierarchy
4. Open Timeline
5. Enter Play mode
6. Observe the behavior of the model
7. Stop the game and in the Timeline remove the Animation track which changes z position of the model
8. Enter Play mode again
9. Observe the behavior of the model

Expected: no matter how many Animation tracks are added for the same object in the Timeline, all the tracks are played at the same time
Actual: if there is two Animation tracks added for the same object in the Timeline, in Play mode only the bottom one Animation track is played

Reproduced in 2017.1.0b2, 2017.1.0b3, 2017.1.0b4
Did not reproduce in 5.6.0b6 experimental build

By design: a second animation track that manipulates the hierarchy (including the root) overrides the first