XRMouseDemoScene throws More Materials Than Sub Meshes warning

Steps to reproduce:

1. Open the attached XRI_360 repro project in Unity 6000.6.0b7. 

1.  

Build Profiles > Android XR build profile > Switch Profile. 

1.  

Build Profiles > Android XR > Build. 

1. Check Console for warnings.

Actual results: 

No Console warnings. 

 

Expected results: 

Mesh 'Plane' has more materials (2) than submeshes (1)

UnityEditor.EditorApplication:Internal_CallDelayFunctions ()

Reproducible with versions: 

Unity 6000.6.0b7 + XRI 3.6.0.

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): 

Warning was seen while building for Aura on MacOS 26.6.1

Notes:

• Flagged as regression – I don't remember seeing this in earlier testing on Aura. 
• I asked Unity AI Assistant which assets in this project cause this warning, and told it that the warning only occurs after adding XRI Starter Assets.  Here is its response:

 

The warning is caused by the sample assets and initialization scripts included in the XR Interaction Toolkit Starter Assets:

 

1. Assets/Samples/XR Interaction Toolkit/3.6.0/Starter Assets/DemoAssets/Prefabs/Interactables/Confetti.prefab

   - Contains a ParticleSystemRenderer configured in Mesh render mode referencing Unity's built-in Plane mesh primitive (`fileID: 10209`).

   - When Unity evaluates the Particle System's renderer configuration (specifically when mesh render mode and secondary material slots such as trail or sub-emitter material slots are present), Unity validates the material array length against the Plane primitive's single submesh, generating the warning: `Mesh 'Plane' has more materials (2) than submeshes (1)`.

 

2. MaterialPipelineHandler.cs / MaterialPipelineHandler.asset

   - Located in Assets/Samples/XR Interaction Toolkit/3.6.0/Starter Assets/Scripts/ and .../Materials.

   - On sample import and domain reload, MaterialPipelineHandler registers a delayed callback (EditorApplication.delayCall += RefreshMaterialPipelineHandlers) to validate and migrate shaders to the active render pipeline (URP / Universal Render Pipeline) and calls AssetDatabase.SaveAssets().

   - When this delayed callback executes via UnityEditor.EditorApplication:Internal_CallDelayFunctions (), Unity saves and re-evaluates the imported sample assets, triggering the console log.