There appear to be a number of times when our build gets hung and can't proceed because of something that has happened with the agent, as if the process has been suspended. In our build log, I can see that the build has hung in the middle of some operation and killing any/all of the build processes doesn't have any effect. If I kill the agent process, though, the build continues as normal, but obviously detached from Bamboo. I've inspected the agent process with Process Explorer and the process is not actually suspended, but I don't know what else is happening to hang the build.

Attached is a thread dump from an agent in the hung state I hope will be useful.