Confluence javascript unresponsive after copy/paste

I tried to paste this URL into Confluence:

https://docs.atlassian.com/jira/latest/com/atlassian/jira/bc/issue/comment/CommentService.html#getCommentsForUser(com.atlassian.crowd.embedded.api.User, com.atlassian.jira.issue.Issue, com.atlassian.jira.util.ErrorCollection)

(The full URL - note that JIRA screws it up too )

The page froze and was giving "unresponsive javascript" errors.
Eventually I had to give up.
I could not save or even copy my work.
Luckily I had and auto-saved draft.

I started working on this, and eventually tried to paste in the same URL again - BANG! same problem.

Some infinite loop in parsing that URL ???