Reproduction Steps:
1. Import attached project.
2. In Build Settings, switch platform to Android.
3. Open "Test" scene.
4. Select "btn_empty" and "btn_play" in Assets.
5. In Sprite Packer, select Pack.
6. Enter Play mode.
7. Exit Play mode.

Expected result: Image in Scene remains the same.
Actual result: Image in Scene becomes corrupted. (GIF attached)

Reproducible with: 5.6.1p3, 2017.1.0f2, 20017.2.0b1
Not reproducible with: 5.5.4f1
Regression introduced in: 5.6.0b1