I don't have time to check it much, but i do think it's something relate to App Store Connect worker service. For this issue, you can use a keys (create in Users and Access) and AppStoreConnect api to remove all images and upload again. Please follow this guide, absolutely work :)

For new app, this error happen too. I'v tested on my production apps and they are all still work, Just new IAP items not work. This will cause the submit for new app or updates got reject for sure.