I'm pretty sure this occurred in the OBJ file. Reading the CL Unimesh script, I see that it does in fact move one vertex outward, so this corresponds with what you're seeing. (I like to do the same thing as a debug test when writing scripts that handle vertices; it's a good way to locate the right index.) I'm guessing that when you spawned a prop, it generated a new OBJ file with the same name as the original?

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