The Naginator plugin creates a link on the project's build page like the following:
Started by Naginator after the failure of build 2018-04-11-143326
Where "2018-04-11-143326" is the name of a build that failed and is hyperlinked to the build output. The hyperlink is:
As you can see, when the build number exceeds 999 a comma is injected into the URL, making it invalid.