Your config is using old namespaces for MRF configuration. They should work for now, but you are advised to change to new namespaces to prevent possible issues later:
* `config :pleroma, :instance, rewrite_policy` is now `config :pleroma, :mrf, policies`
* `config :pleroma, :instance, mrf_transparency` is now `config :pleroma, :mrf, transparency`
* `config :pleroma, :instance, mrf_transparency_exclusions` is now `config :pleroma, :mrf, transparency_exclusions`