Branch build fails with no log and self-disables

[Mark Wolff]

I have a plan branch that has been running 300+ times.  Recently when this plan is executed it stops immediately, it has no logs, it self-disables, it is not in the "recent build list" and does not show an error to the administrator.  I've restarted the agent with no success.  If I run the commands manually as the user that runs the agent, the process works.  I've used Bamboo for 10+ years and never had this level of "no info" from a build failure before.  What else should I try?