Quote - Trouble is, these scenes often have copyright content in them, such as V4, so I don't give them to SM, under the assumption that I'm not allowed to. Maybe I'm mistaken and it is allowed. Further, I'm sure somebody at SM already has V4. But I don't know what is permitted.

The problem with PZ3s isn't usually the geometry for figures (this should be an external call to the OBJ) or textures (always external references), but the geometry for props (which is internalised) and morph data (when internalised).

If you can still get the bug to show up when all morphs have been dropped (relatively easy) and no textures applied, then you only have to worry about SM having a copy of the figure OBJ.
I suspect the real problem is that the occurence of the bug is too dependant on everything being "just so", which means your left with trying to get it to appear with only the content supplied with Poser.
The other approach is to review the code asking the question "What could cause a bucket to return nothing or cause it to fail to return anything ?"