Sometimes two parallel builds on our Jenkins server are combined into one build. when that happens, the first build gets all the artifacts attached to it, the second build is not listed in jenkins. See the attached screenshot how it looks like on the first build page.

As you can see the build data for the moudles is there, also the links for both builds work, the second build is just assigned to the wrong "parent".

In this case here build 4785 failed, but the gerrit trigger plugin notified the failure on the commit of build 4784.