To reproduce:
1. Open attached project
2. Push project to collab
3. Download and open project from collab in the other computer
4. Open SoundController prefab which is in Assets -> Free Lives Commonwealth on 1st computer
5. Add new song on 1st computer Sound Holder ->Sounds-> Clips as Element 0
6. Update project in Collab on 1st computer
7. Update project on 2nd computer

Expected result: Element 0 audio clip will change in updated project on 2nd computer.
Actual result: Element 0 audio clip changes to 'None'. Restarting Unity fixed this problem.

Reproduced on:
5.5.0b11, 5.5.0b10, 5.5.0b8