Desync between the Render and Game Threads?

Recently I’ve encountered frame rate issues with one of my projects. Upon Unreal Insight investigation, it’s revealed that a ton of time is wasted with the CPU or GPU waiting for tasks to finish! The CPU and GPU frames are misaligned too, likely causing this.

This was recorded on Android on the Meta Quest 3.

What on earth could be causing this desync?

Screenshots of issue: