This behaviour still occurs when testing a URCap built with SDK 1.5 in a simulated in 3.9. I don’t know if this is an SDK bug or a polyscope bug, so it would probably be worth trying a 1.6 cap in 3.9, but you’re right it’s probably not been fixed in the 3.9 update, as it isn’t mentioned in the list of bug fixes. Hopefully it will be fixed come 3.10.