This issue is NOT duplicate. While trying to identify spikes in gameplay, a coroutine was showing very heavy call's and cpu usage. The name of the coroutine from the hierarchy had nothing to do with the coroutine that was ACTUALLY causing the spikes. It seems that Unity's profiler was picking random coroutine method names instead of accurately posting the specific coroutine that was causing the problem.

If we removed the coroutine that was showing up as the culprit of cpu usage, the profiler would just show some other arbitrary and completely unrelated coroutine.

This was discovered for us with Unity 5.5.1f1