The naming restrictions are illogical.

For healthy permissions set, naming restrictions should be the same for pagePath and assetFolders

Example:

If you have a page with path /Test/test you can't create an assetFolder with name 'Test' to upload the assets because of uppercase restriction.

So you need to set two page rules, one for the page path "Test" and one for read/manage assets of 'test' folder.