https://tickets.metabrainz.org/browse/MBS-12904?focusedCommentId=67455&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-67455

 So far the only workaround I've found is to add another URL or just a space will do and then remove it again.

Applying the workaround however still leads to the loss of entered relationships. Created a new work and standalone recording. Both were created but the performance of relationship was not applied.
https://musicbrainz.org/recording/921e7676-7f7c-4543-8839-cb96150c3631/edits
https://musicbrainz.org/work/3000a028-64b5-49ef-9353-efd6d50b80df/edits

Lost relationships were mixer, vocals and "recording of". Notably artists in relationships and recording artist credit are the same.