At least root/release/index.tt does its own ad-hoc serizalizing of entities, where only the fields important for the task at hand (here, displaying a release) are included. This is dangerous because of the client-side entity caching: Only the first version of any entity encountered is kept, all later versions are replaced by it. This may lead to mysterious bugs, or to bugs being mysteriously concealed sometimes; see https://bitbucket.org/metabrainz/musicbrainz-server/pull-request/1192/mbs-6088-serialize-edits_pending-in/diff#comment-2960060 for an example of the latter.

This template and possibly other places that do ad-hoc serializing should be changed to use the standard serializers that are used by ws/js.