Reproduction steps:
1. Open project attached(Repro.zip).
2. Open scene "0" from Assets folder.
3. Press play.

Expected result: Game will switch scenes instantly.
Actual result: It takes about 15-25 secs.

Notes: Shader has an error "Static/StaticShaderOneSide_S: failed to open source file: 'StaticEffect.cginc' at line 27"
When you press play, it should should switch from scene "0" to scene "1".
Huge load time also detected after dragging prefab (Assets/Resources/WeaponShelfTest/WeaponShelf) to scene while being in play mode and then pressing stop.

Workaround: Make materials to use standard shader instead of "StaticShaderOneSide_S".

Reproduced on: 5.5.2f1, 5.6.0p2, 2017.1.0b1