To reproduce:
1. Open "Example.zip" project.
2. Open "scene2".
3. Delete "Cube(Clone)" in Hierarchy, and save scene.
4. Build and Play project.
5. Cube still appears.

Expected result: Code which is executed in "if UNITY_EDITOR", should not have effect on the Build version.
Actual result: if a class is [ExecuteInEditMode], all objects created in it's Awake() function under the "if UNITY_EDITOR" appear in a build.

Reproducible with: 5.4.4p4, 5.5.2p1, 5.6.0b10, 2017.1.0a2

Workaround:
Change Awake() to Start().