The most plausible cause is that the two environments are resolving asset identifiers differently. NVIDIA's Learn OpenUSD glossary defines asset resolution as the process of translating an asset path into the actual location of a consumable resource, and identifies ArResolver as the plugin point that can be customized to resolve assets through site logic, databases, or version-control systems.

Option C is correct because the same authored USD layer can contain references, payloads, textures, or other asset-valued paths that are resolved at runtime. If one user's resolver context maps @character.usd@ to version 12 while another maps it to version 15, or if one environment cannot resolve a dependency at all, the composed stage can differ. This can manifest as missing geometry, stale geometry, missing materials, or unresolved payloads. Reference and payloads are composition arcs that bring external scene description into the stage, so resolution differences directly affect what data is available for composition.

Option A is incorrect because USD does not change composition semantics based on available memory. Option B is not the primary explanation here; instance prototypes are derived from composed instance data, but the root problem described is inconsistent asset resolution. This aligns with Debugging and Troubleshooting Asset Resolution, Reference, Payloads, Resolver Contexts, Missing Dependencies.