Goldie, as stated earlier, the "design flaw" you described is not a design flaw as this plugin is already designed to sync permissions without reloading. You are either experiencing a bug with the plugin or an issue with your oxide permission groups, likely the latter.
Have you reproduced this when granting permissions to individual players? Have you reproduced it with other groups such as default and admin? Have you reproduced this on multiple servers using the same configuration (such as a local test server)? Can you also paste your configuration? Are you opening the backpack before the permission is granted?
Have you reproduced this when granting permissions to individual players? Have you reproduced it with other groups such as default and admin? Have you reproduced this on multiple servers using the same configuration (such as a local test server)? Can you also paste your configuration? Are you opening the backpack before the permission is granted?