It is a bug, I posted a bug report on it weeks ago, it's never been reproducible, and it isn't fixed yet. I hardly ever see it since SR1 - maybe once. If you have a scene that can make it happen more than one in a thousand renders, maybe SM should have that scene.

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.

That's a flaw in CG copyright, IMO - I should be able to give a copyrighted content item to SM for them to reproduce a bug in the software. There should be some "bonded vendor" notion, where, similar to a Non-Disclosure Agreement, they are legally allowed to receive the copyright content for debugging purposes, and then delete it.

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)