Reproduction steps:

1. Open "MinimalRepro.zip" project
2. Open "Main" Scene
3. Enter Play mode
4. See that the movement sometimes stutters
5. Build the project
6. Open the Build
7. See that there is no stuttering

Expected Result: No stuttering occurs
Actual Result: The Game window stutters in the Editor, but not the Player

Reproduced with: 2018.2.0a2, 2018.1.0b9, 2017.3.1p2, 2017.2.2f1, 2017.1.3p1