I tried to remove a recording-level liner notes relationship on https://musicbrainz.org/release/307f3c08-78de-4d64-ba0d-574776177669/edit-relationships and got an ISE. Possibly because this relationship type is now deprecated.

See attached file for a form with the data it posted.

Error:

Caught exception in MusicBrainz::Server::Controller::RelationshipEditor->base "Can't call method "entity0_type" on an undefined value at lib/MusicBrainz/Server/Form/RelationshipEditor.pm line 140, line 3."

Stack trace:
line 140 MusicBrainz::Server::Form::RelationshipEditor
line 15 MusicBrainz::Server::Form
line 36 MusicBrainz::Server::Controller::RelationshipEditor
line 326 MusicBrainz::Server
line 300 MusicBrainz::Server
line 327 MusicBrainz::Server
line 341 MusicBrainz::Server
line 386 MusicBrainz::Server

Request data:
$VAR1 = {
'query_parameters' => {},
'body_parameters' =>

Unknown macro: { 'rel-editor.rels.0.attrs.additional' => '0', 'rel-editor.as_auto_editor' => '1', 'rel-editor.edit_note' => '', 'rel-editor.rels.0.entity.0.gid' => '0c1132ec-2b62-4f98-9eb3-f294eba4ced2', 'rel-editor.rels.0.link_type' => '131', 'rel-editor.rels.0.entity.0.type' => 'artist', 'rel-editor.rels.0.period.ended' => '0', 'rel-editor.rels.0.entity.1.gid' => 'b406dbcb-5aa0-4ff8-8fc2-f0cf4ac3ad59', 'rel-editor.rels.0.entity.1.type' => 'recording', 'rel-editor.rels.0.id' => '1126906', 'rel-editor.rels.0.action' => 'remove' }

};

Host: pingu

URL: https://musicbrainz.org/relationship-editor