Very simple builds where Build A triggers build B and waits for completion results in the following output:

Started by user anonymous
Building in workspace C:\JW\A
Waiting for the completion of B

And even after B has completed, A never finishes. Configuration files for builds A and B are attached.

I tested this in all the versions of Jenkins mentioned in the Environment section above and it was present in all of them.

The problem seems to be caused by the SCM Sync Configuration Plugin. I tested it with a fresh install of Jenkins 1.473 and only the two plugins for SCM Sync and Parameterized Trigger enabled and the bug was present. Disabling SCM Sync caused it to go away.