Problem with Sticker Extension icons not working

I'm using PBXProject.AddAppExtension in my Post build process to add my sticker extension to my final Xcode project but I've hit a dead end with the sticker icons assets.

With the extension in Xcode, even if I create a new asset pack and new sticker icons, they don't get built, so I have a null icon in Messages and archiving and uploading to the iTunes store just gives me missing icons errors.

If I manually add a new extension target in Xcode, adding icon assets to it work, but even those working icon assets won't work in the Unity created extension.


There's another bug that comes up during the upload process too, which may be linked. It seems the extension bundle somehow has a disallowed file 'Frameworks' in it (nothing in the build process for the extension in Xcode lists it either).

Anyone come across this or know if it's just some oddity with the AddAppExtension functionality?

I'm using Unity 2017.10f3 and Xcode 9 beta (also tested with same results in Xcode 8).