How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a MaterialPropertyBlock Not Affecting GPU-Instanced Renderers in Unity

Q: What causes a MaterialPropertyBlock not affecting GPU-instanced draws?

The shader property is not declared inside an UNITY_INSTANCING_BUFFER, so per-renderer values from the property block are not packed into the instance data and every instance uses the shared material value.

Quick answer: Declare the property with UNITY_DEFINE_INSTANCED_PROP inside an instancing buffer and read it via UNITY_ACCESS_INSTANCED_PROP, then set it through SetPropertyBlock per renderer.

GPU instancing batches identical draws, so per-instance overrides only work if the shader explicitly reserves space for them. A MaterialPropertyBlock that targets a non-instanced property gets ignored on batched draws. Here is how to fix it.

How to fix it

1. Declare the property per-instance

Wrap the property in UNITY_INSTANCING_BUFFER_START(Props) UNITY_DEFINE_INSTANCED_PROP(float4, _Color) UNITY_INSTANCING_BUFFER_END(Props) so each instance carries its own value.

2. Add the instancing setup macros

Ensure the vertex and fragment stages call UNITY_SETUP_INSTANCE_ID and the struct includes UNITY_VERTEX_INPUT_INSTANCE_ID, then read with UNITY_ACCESS_INSTANCED_PROP(Props, _Color).

3. Set values via property block, not material

Call renderer.SetPropertyBlock(mpb) per renderer; do not call renderer.material, which instantiates a unique material, breaks the batch, and defeats instancing entirely.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.