We have a job that has the Execute Build Concurrently enabled and is triggered by git pushes. The build time varies depending on the changes that were made. So one run could take 20 minutes, while the next one takes 10.

The problem is when a long running build is triggered and then a fast one after that. The fast one finishes, then waits for the slow one before triggering all the post-build actions or releasing the executor.

See the following thread dump from the master node: http://pastie.org/private/ie4vqghl4tc1g8giifpqq

This is a "major" issue for us because there is no work around that we can find, and it is preventing our build pipeline to complete, delaying the final results of the build.