Steps to reproduce:
1. Open QA's attached project
2. Open scene "scene"
3. Select "Main Camera"
4. In the Inspector scroll down and check "Disable Original Rendering"
5. Press play

Expected result: All animations are playing in sync
Actual result: Hand and weapon animations are out of sync

Reproduced with: 5.6.3p1, 2017.1.1f1, 2017.2.0b10, 2017.3.0a6

Note: When "Disable Original Rendering" is unchecked, the animations are synced