(Oculus Rift) Spikes in “GPU Usage – Other” causing frame freezes. Can I avoid this?

The main issue I’m encountering is that the screen image sometimes freezes momentarily and this causes simulator sickness in participants, especially when rotating the head / look direction.

The profiler shows a spike happening in the “GPU Usage” section, specifically under the “Other” heading which I believe is the cause of this freezing of the image.

Why is this? And am I able to avoid this or mitigate it somehow?

Thanks, Jason.