Just ran into a problem with downstream-ext 1.3, Hudson 1.342, Perforce plugin 1.0.17.
I have a build X which I have set to trigger builds A, B, and C on success, but only if there are SCM changes. A, B, and C is the order that the downstream jobs are tested for SCM changes when I look at the logs.
The problem is that when build B is already running, the polling appears to hang for job B. After many minutes, I aborted the job, which generated in the logs:
The polling for C then proceeded without incident. This happened on two consecutive builds, so that's enough for me to not call it a random failure.
Build B is a very long-running build... I haven't yet run into the situation where A or C were running at the time of the completion of X.