Me and my team have noticed that the link editor popup is broken for any Confluence pages with parenthesis () in the title.
Right now, the workaround is to 'unlink' and recreate the links, but this is a counterintuitive and time consuming process.
I found that this was a bug in the past that has been marked 'resolved'. I think it should be reopened: https://jira.atlassian.com/browse/CONFCLOUD-54772
https://community.atlassian.com/t5/Confluence-questions/How-do-we-request-a-bug-issue-be-reopened/qaq-p/2279891
