Why am I getting an invalid pom due to the absence of dependency.version, although the version is managed?

I have a case that looks like this:

super

• thrid-party dependency setup

parent-pom

• super baby

Projecta STRONG>

• parent-pom child
• third-party addiction

projectB

• parent-pom child
• projectA dependency

projectA builds just fine, but when I try to compile projectB, I get:

[WARNING] POM for [projectA] is not valid, transit dependencies (if any) will not be available: 1 problem occurred while creating an effective model for [projectA]

[ERROR] 'dependencies.dependency.version' for thrid-party.jar is missing. @

Any idea why?