Introduced by https://ono.unity3d.com/unity/unity/pull-request/99050//lighting/plm/lightcookies

OpenCLCommonBuffers::PrepareLightCookiesBuffer is called 500+ times during the bake, because SetSceneStateOnTechnique(this) is called from RadeonRaysBakeLightProbesTechnique::Render()!

This should only be done once, in RadeonRaysBakeLightProbesTechnique::AttachHeavyDataPointers. SetSceneStateOnTechnique isn't tread safe so this can also cause crashes if scene state is changed while baking.

Performance hit was visible in https://confluence.unity3d.com/pages/viewpage.action?spaceKey=teamgi&title=Light+cookie+support+for+PLM but ignored. The more light probe groups and the higher sample counts you have, the worse it gets.

https://ono.unity3d.com/unity/unity/pull-request/99050//lighting/plm/lightcookies landed in trunk at 2020.1.0a22.2693_a851a673d667