Status: Resolved (View Workflow)
Resolution: Not A Defect
A Job-A is triggered by Job-B. This is configured via "Build after other projects are built" configuration in JobA.
In terms of behaviour, everything is fine : Job-A is correctly triggered after a build of Job-B.
But in Job-B configuration, the "Build other projects" in Post-build Actions section isn't configured. This section should be filled with a Job-A trigger but it's empty.
The inverse is also true : if a Job-D is triggered by a Job-C via "Build other projects" in Post-build Actions section of Job-C, Job-D "Build after other projects are built" section is empty.
Note : https://groups.google.com/forum/#!topic/jenkinsci-users/MEjz9N38bus
While previously "Trigger after other project" was just a pseudo-trigger that actually configured the upstream project to add a "Trigger other project" post-build step, now they're completely separate.
You can either choose to have upstream trigger downstream, or have downstream monitor upstream for completion.
This is also relevant due to permissions if not all users are able to see all jobs, as you can only configure job references to jobs you can see.
Not a defect, these have been decoupled a while back (in 1.560) to be less weird. Otherwise users able to configure Job-A would effectively be able to change the config of Job-B.