Two unrelated modules A and B. According to the parent pom, B is built after A (but does not depend on it).
1. John makes a commit to module A that breaks it.
2. Hudson forks a build that compiles module A and fails.
3. Paul makes a commit to module B that breaks it also.
4. Hudson forks a build that intends to compile module B, but first compiles module A (it is still failed) and fails.
5. John fixes module A.
6. Hudson forks a build that compiles A only (B is not among its dependencies).
==> Build is marked successful while there is a "hidden time-bomb" in module B.