This appears to happen intermittently; perhaps an issue on only one of the servers?

Internal Server Error
Oops, something went wrong!

Error:

Caught exception in MusicBrainz::Server::Controller::Artist->edits "Can't locate object method "clone_instance" via package "Class::MOP::Class::Immutable::Moose::Meta::Class" at /home/musicbrainz/musicbrainz-server/script/../lib/MusicBrainz/Server/Edit/Historic/MoveRelease.pm line 48."
Stack trace:
line 48 MusicBrainz::Server::Edit::Historic::MoveRelease
line 479 MusicBrainz::Server::Data::Edit
line 42 MusicBrainz::Server::Controller::Role::EditListing
line 18 MusicBrainz::Server::Controller::Role::EditListing
line 270 MusicBrainz::Server
Request data:

$VAR1 = {
'query_parameters' => {},
'body_parameters' => {}
};

URL: http://musicbrainz.org/artist/dc4caab0-9fdb-4dca-9b10-257fa7393e3e/edits