Rendering pivot painter wind WPO foliage in Path Traced vs. Deferred

Guys, do you have any idea or insight, why my PivotPainter Foliage Instances behave so weirdly when rendered in PT - looks a bit like they are shaking in unison instead of organically!?

Important: Renders completely fine when working with static meshes instead of instances.

Using this cvar: r.RayTracing.Geometry.InstancedStaticMeshes.EvaluateWPO 1