After installing the new hudson.war made available by olamy which fixed JENKINS-8387, I still got the same problem during deploy phase.

Everything works for a "clean install", but for a "clean deploy" things get a little messy: build two times in a row made the first build ok, but the second failed during deploy phase (access denied to Nexus).

The difference between the builds is that on the first one, maven had to download some dependencies. The second time everything was already in the local repository. If I manually remove some of my project dependencies, the build will work one more time, and then break if I build again.

More info: http://hudson.361315.n4.nabble.com/Maven3-builds-won-t-authenticate-with-nexus-td3175639.html