Repro steps:

1. Open Scene1 from the attached project.
2. Select the directional light and rotate it; observe the particle rotating
3. Turning off shadow casting on the light, or on the particle system resolves the issue.

Notes:
- Issue introduced in 2018.1
- Affects View and Facing render alignments
- Only in Forward Rendering mode

RichardK Note:
It's happening because m_MeshGPUInstanceData is a single ComputeBuffer on the particle renderer, so the shadow job overwrites it, and then the main render uses the overwritten data.

AcquireExclusive on the dynamic VBO needs to support compute buffers, to fix this, instead of allowing the particle system to control its lifecycle.
If we make DynamicVBOBuffer store the buffer type, we can change GfxBuffer* to be a union with ComputeBuffer*.