RiveTextureRenderer shows Rive "R" logo placeholder at runtime, editor preview renders correctly

Description

In my project, the Rive Panel's editor preview correctly displays my artboard when selected in the Scene view, but at runtime in the Game view I see the Rive "R" logo placeholder instead of my animation. The asset, artboard, and state machine are all assigned and visible in the inspector.

Steps to reproduce

1. Create a Rive Panel via right-click → Rive → Rive Panel
2. Add a Rive Widget child and assign a custom .riv asset, artboard, and state machine
3. Add a Quad with MeshRenderer + Rive Texture Renderer to display the panel in 3D world space
4. Enter Play mode

Expected behavior

The Quad displays the animation that's visible in the Rive Panel's editor preview.

Actual behavior

The Quad displays Rive's "R" logo placeholder texture. The actual artboard content never renders at runtime, only in the editor preview.

Environment

• Unity version: Unity 6.3
• Render pipeline: Built-in
• Rive Unity package version: 0.4.0
• OS: Windows
• Target platform(s): Standalone Windows

What I've tried

• Confirmed Graphics API for Windows is set to Direct3D11 first (Auto Graphics API off)
• Verified the asset, artboard name, and state machine name are correctly assigned in the Rive Widget inspector
• Confirmed the editor preview renders the animation correctly when the Rive Panel is selected in Scene view

Console output

No Rive-related Console output

Screenshots

Reproduce the issue in Unity 6.3 with the Built-in pipeline and Direct3D11, then trace runtime initialization from RiveTextureRenderer and the Rive Panel/Rive Widget path. Done means the Quad's MeshRenderer displays the assigned artboard animation in the Game view instead of the Rive "R" placeholder.