Particles render inconsistently in model thumbnails based on hierarchy

Models containing particle/vfx instances fail to render in model thumbnails unless parented to a part with a mesh (MeshPart with MeshId or Part with SpecialMesh). This may be related to the recent accessory thumbnail particle rendering update being inherited by models. I was able to occasionally get particles to appear on parts without meshes parented to models, but the same setup also failed so I am somewhat confused on what actually triggers it to break.

Results:

  • Sparkles and ParticleEmitters only show if parented to a MeshPart with a MeshId
  • MeshParts without a MeshId do not render Sparkles or ParticleEmitters
  • Fire always shows regardless of setup
  • Smoke doesn’t appear at all (I am unsure if this is intentional)
  • Regular parts do not render particles unless they contain a Mesh

Visual Aids:

Part (broken): part lol.rbxm (6.0 KB)
Handle (working): meshpart.rbxm (8.1 KB)

All these models I uploaded contain sparkles and the ones that show use the MeshPart with MeshId setup, the ones that do not show are regular parts

Expected behavior

All particle/vfx instances should render in model thumbnails regardless of the hierarchy like they used to