Hello,
Nanite meshes will keep the fallback mesh loaded at all times.
You can try reducing the memory impact from fallbacks by reducing the “Fallback Triangle Percentage” only. However, this can affect use-cases that need the fallback.
This ticket discusses the Nanite Fallback in more detail, including it’s uses at runtime:
[Content removed]
Reducing the Keep Triangles Percentage reduces the fallback indirectly by reducing the Nanite mesh used to generate the fallback.
Here are some other tickets discussing Nanite memory management:
[Content removed]
[Content removed]
[Content removed]
[Content removed]
[Content removed]
Please let us know if this helps.