Bug Massive FPS drops in small VR testing environment - GPU Profiler "Other"

Unity version: 2020.3.7

I've run into an issue while working on a small VR project using Hurricane and Final IK. For reference the scene includes just two player models(one is a static test dummy) and nothing else but a floor.
Recently I've started to experience huge lag spikes which seem to occur completely at random but rather frequently, and when attempting to debug the cause it seems to lead back to the GPU "Other" category, which the documentation simply lists as "Rendering time to process other things such as Scriptable Rendering Pipelines". I initially did not have any render pipeline set up so I added URP v10.8.1 and the problem persists. It doesn't seem to be related to what is being rendered at the moment the FPS drops occur, and the only other noticeable change in the profiler is a drop in the number of kinematic rigidbodies - which I assume is simply because they are not being updated during the freeze.

I'm looking for advice on possible causes for these performance spikes, or even advice on how to further debug this vague "Other" listed under the GPU profiler so I can see what exactly is the cause. These screenshots show the issue occurring at two different times, the large animator and renderer processes taking over the CPU are caused by Semaphore.WaitForSignal which seems to just be waiting for the GPU process to complete, and this aligns logically with the CPU ms count rising in line with the GPU, but one frame behind.