Steps to reproduce:
1. Open the attached “IN-142712“ project
2. Open the “Scenes/SampleScene” scene
3. Select the MainCamera GameObject
4. In the Timeline window, drag the current time marker past the entire “VFX” activation track
5. Repeatedly keep extending the Activation Track by small increments until you reach the border of the window
6. Observe the crash

Reproducible with: 6000.3.0a3, 6000.3.15f1, 6000.4.7f1, 6000.5.0b8, 6000.6.0a5
Not reproducible with: 6000.0.75f1, 6000.3.0a2

Reproducible on: macOS 26.4.1 (M1 Max)
Not reproducible on: Windows 11, macOS 26.4.1 (Intel)

First few lines of StackTrace:
#0 0x000001061e24d0 in StoredGraphicsBuffer::GetGfxBufferID(VFXValueContainer const) const
#1 0x00000106234aa8 in void VFX::CastVFXValueParam<VFXMaterialUniformUploader, VFXExpressionValueWrapper>(VFXMaterialUniformUploader&, VFXExpressionValueWrapper const&, VFXValueType)
#2 0x0000010620ed94 in void VisualEffect::PrepareTask<VFXMaterialUniformUploader>(VFXMaterialUniformUploader&, VFXTaskDesc const&, bool) const
#3 0x0000010620ec1c in VisualEffect::PrepareMaterial(Material, VFXTaskDesc const&, bool) const
#4 0x000001061bc380 in VFXParticleSystem::UpdateMaterialCommand(void*)
#5 0x000001061f2b70 in VFXManager::PrepareCamera(Camera const&, VFXCameraXRSettings const&)