Blender Geometry Nodes → Cycles Render Engine: Does Execution Order Affect Render Output?

Integration Boundary: Geometry Nodes and Cycles

The goal is to determine whether the execution order of Geometry Nodes that modify the same mesh and feed into a single downstream node is explicitly defined in Blender’s documentation. Current evidence suggests the order is undocumented, potentially leading to unpredictable vertex positions and shading artifacts that differ between Blender releases and hardware configurations.

Key constraints include version variability (Blender 3.4 vs 3.5+), GPU acceleration introducing nondeterminism, and the risk that complex node trees mask the issue. A minimal test scene is required to isolate the problem and verify consistency across CPU and GPU.

Unresolved questions:
1. Is the node execution order deterministic across Blender releases when multiple Geometry Nodes output to the same downstream node?
2. Does GPU acceleration modify the implicit execution order, causing divergent render outputs?
3. Can a minimal test scene reliably expose and document the order ambiguity?