Given the following constellation.

Project A 1.0-SNAPSHOT (POM only)
Project B 1.0-SNAPSHOT (Jar, has A as parent)

Both jobs use private Maven repositories.

Both projects have a separate job.

Change something in project A, commit. Job A builds and deploys to repository

Change something in project B that dependes on changes in project A. Commit. Job B starts an resolves the POM using the old parent POM, potentially leading to a broken build.

For example: B declares a dependency WITH a version. Now remove the version from B and enter a dependencyManagement entry into A. Commit A, later B.
Result: B fails because pom validation has no valid version for the dependency.

Only solution (since private repositories are used): Clean workspace of B via Webinterface, the rebuild B.