You can "inject environment variables" in the "Build Environment" section, or as a build step.

In a Maven project type, when I use a build step (pre build step in this case), the properties were not available in the maven step, whereas it worked when I used the Build Environment setting.

In a Freestyle project, both version worked.

Expected: A Pre build step "Inject Environment Variables" in a Maven Project should make those properties available to the main Maven build step