In order to enrich the Stackoverflow content for others, that like me, found this post as a way to solve the "problem" of ${maven.build.timestamp}. This is not a maven bug, but an expected behavior of m2e, as can be seen in this post.
Therefore, I believe that we can not expect the solution to be "corrected", since, from what I understand, the correction involves conceptual issues.
In my case, what I did was use the plugin (buildnumber-maven-plugin) as described in this other post.