I went to https://musicbrainz.org/release-group/afc89468-9c40-4436-ac09-3a98fbd7e5a6/aliases and hit "Add a new alias", which brought me to https://musicbrainz.org/release-group/afc89468-9c40-4436-ac09-3a98fbd7e5a6/add-alias which was an error screen with this:

TypeError: Cannot read property 'aliases' of undefined
at t.default (/home/musicbrainz/musicbrainz-server/root/static/build/server-components.js:1:506843)
at d (/home/musicbrainz/musicbrainz-server/node_modules/react-dom/cjs/react-dom-server.node.production.min.js:33:498)
at bb (/home/musicbrainz/musicbrainz-server/node_modules/react-dom/cjs/react-dom-server.node.production.min.js:36:16)
at a.b.render (/home/musicbrainz/musicbrainz-server/node_modules/react-dom/cjs/react-dom-server.node.production.min.js:42:43)
at a.b.read (/home/musicbrainz/musicbrainz-server/node_modules/react-dom/cjs/react-dom-server.node.production.min.js:41:83)
at Object.exports.renderToString (/home/musicbrainz/musicbrainz-server/node_modules/react-dom/cjs/react-dom-server.node.production.min.js:52:138)
at getResponse (/home/musicbrainz/musicbrainz-server/root/server/response.js:102:31)
at Socket.receiveData (/home/musicbrainz/musicbrainz-server/root/server/createServer.js:83:31)
at Socket.emit (events.js:198:13)
at Socket.EventEmitter.emit (domain.js:448:20)