To reproduce:

1. Open the project, attached by the user (3dSoundTest.zip)
2. Open the "default" scene
3. Enter Play mode
4. Hear that sound is not in the middle even though the Spatial Blend of Audio Source is 0.
5. Try changing the Pitch or Volume of SoundSourceObject

Expected: Audio Source properties are not ignored when Audio Source is in Timeline Audio Track

Reproduced in 2017.1.3p2, 2017.2.2p1, 2017.3.1p4, 2018.1.0b11, 2018.2.0a3
Did not reproduce in 2018.2.0a4, 2018.2.0a5

Fixed in 2018.2.0a4