Sprite playback in the Animation Window repeats frame 16.

Repro:
1- Open attached project.
2- Open scene "ReproScene".
3- Select game object "New Sprite".
4- Open animation window and scrub to frame 16. Sprite matches associated thumbnail in the dopesheet (good).
5- Scrub to frame 17. You'll see that scene view still shows frame 16 and doesn't match thumbnail in the dopesheet (bad).

Reported by user: https://forum.unity.com/threads/animation-issue-using-spritesheets.527377/

Reproducible: 2018.3a1, 2018.2b2, 2017.1.0p3