Is this actively being worked on and investigated? I remember raising this issue over a year ago, and then again in November. At the minute it's just another new feature that doesn't quite work. I now leave it turned off. In a live production environment it's too hit and miss to chance it and leave a render going only to come back and discover it's got these issues, because there's no guidance on specific setups where we might encounter it. It's just a case of press render and hope the render doesn't have artifacts when you come back to it. Safer to just leave it off permanently imo until it's fixed.