How to reproduce:
1. Open Unity
2. Download and open 'Survival Shooter' demo
3. Open '_Complete-Game.unity' scene
4. Open 'Player' GameObject Animator
5. Press 'Pause' button
6. Press 'Play' button
7. Change first Animator parameter
8. Perform a frame step
9. Check console for errors

Expected result: No errors are present in the console
Actual result: An error message pops up. Its content depends on the Unity version on which the project is run.

Reproducible with - 2017.3.0a1, 2017.3.0b10, 2018.1.0a1, 2018.1.0a5
Not reproducible with - 5.6.4p3, 2017.1.2p3, 2017.2.0a1, 2017.2.0p2

Notes:
* Reproduces randomly but is not rare to get it.

Verified in: 2018.1.0b1