Reproduce
1. Open user attached project
2. Press File/Build & Run to build a Windows Standalone 64bit player
3. Start Player
4. Connect Profiler to running Player
5. Select in Profiler Update.ScriptRunBehaviourUpdate/BehaviourUpdate/TestCode.Update()

Expected result: TestCode.Update() will take only very small amount of time.
Actual result: TestCode.Update() takes undetermined amount of time to finish.

Note: When the code is put into LateUpdate, those spikes do not appear.

Reproduced on: 5.5.0f3, 2017.1.0p5, 2017.2.0b9, 2017.3.0a6