DrawMeshInstancedIndirect not working in Hololens2

Using the DrawMeshInstancedIndirect sample code from the docs on a clean 2020.3.30f1 OpenXR project following the Microsoft recommended setup and the instance geometry is only rendered in the left eye while normal models are rendered correctly in both. Appears to be an issue with the Single Pass Stereo Rendering being used with this. Any suggestions on how to fix this (without resorting to slow multi-pass rendering)?

Can anyone explain what this statement in Single Pass Instanced rendering docs means as I think it may be relevant.

Procedural geometry: When using the
Graphics.DrawProceduralIndirect() and
CommandBuffer.DrawProceduralIndirect()
methods to draw fully procedural
geometry on the GPU, it is important
to note that both methods receive
their arguments from a compute buffer.
This means that it is difficult to
increase the instance count at run
time. To increase the instance count,
you need to manually double the
instance count contained in your
compute buffers.

See Vertex and fragment shader examples for more information on how to write shader code.