Burst mode keeps dropping with Mayhem build?

Is this a common thing or supposed to happen?

Every time I zone, Finish a cinematic, Etc it will randomly drop and put me into “Exhaustion” mode. Happens quite often. Seems like a flawed part of the mechanic / build.

It happens to my buddy who is playing the same build, and he complains about it constantly. I really hope its something they can end up fixing.