Unable to upload/download release assets with GitHub app

I’m trying to use a GitHub app in my CI to upload/download assets to a release, but I seem to have stumbled onto an oversight in the permissions model for GitHub apps and release assets.

The download needed a bit of a hack (add the token to the URL, set the Accept header) but failed with a permission-based error:

{"message":"Must authenticate to access this API.","documentation_url":"https://developer.github.com/enterprise/2.21/v3"}

The upload got a bit further, but eventually dies with a 502 (error from pygithub):

github.GithubException.GithubException: 502 {"message": "Error uploading to https://media.github.<redacted>/releases/27772/files: 404", "request_id": "f39b193b-0ec4-11eb-88ef-9f68efc3c470"}

For uploads, there appears to be no permission for enabling access to https://developer.github.com/v3/repos/releases/#upload-a-release-asset per https://developer.github.com/enterprise/2.21/v3/apps/permissions/#permission-on-contents.

Is there any way to request additional permissions be added to the GitHub app to support this? I’m running this against my company’s GitHub enterprise instance v2.21 but see nothing to suggest this works on public GitHub either.