Turns out not all gem versions were aligned with the ones used in in.relation.to. In particular a different (earlier) version of eventmachine was used which native extensions would not compile on Fedora. I aligned the gem versions.

Steve Ebersole, could you try to run the following steps after updating the production branch:

$ rake clean[all]
$ rake setup
$ rake preview

(First time around it preview execution will be slow, since it will cache the release poms)