Details:
When running a single build concurrently : ie build 9 and 10.

If 10 completes before 9, the Jenkins dashboard still indicates that 10 is in progress.

However when examining Build 10's status page, it indicates it has completed.
The console for Build 10 is constantly polling as well, instead of indicating it has completed.

This holds up an executor, which is a waste of resources.

Expected behavior
Build 10 should indicate that it's complete and that the executor is free.

Additional Info:
Build 9 is running a lengthy external java process via bat/shell