Ever since 5.2 came out, we have been getting enormous spikes (like 40ms) every second or two from what the profiler is calling "WaitingForJob." I've seen people asking about this before, but they always report seeing the WaitingForJob item underneath the Camera.Render and Culling. This is not the case for us. This WaitingForJob is a root-level entry in the list, totally separate from the WaitingForJob that occlusion culling shows (and we're not even using built-in occlusion culling at all)....
WaitingForJob (not related to occlusion culling)
WaitingForJob (not related to occlusion culling)