title: TeamCity spuriously triggering when no changes
body: <p>I am using TeamCity 8.05 with github and feature branches.</p>
  
  <p>I have a problem that team city will sometimes trigger a build on a feature branch for reasons unknown. It happens overnight or over a weekend when the server is idle. If I click on the build changes its always an old feature branch with no changes for several months.  I have no idea why this would cause a build trigger.</p>
  
  <p>Its also very inconsistent - we can go for a week or 2 with no spurious builds and then we will come in one morning and team city has overnight built 6 old feature branches and deployed an random old release.  None of these branches have any recent github activity and have been built by TC in the past (when the last changes where made).</p>
  
  <p>Does anybody have any idea whats going on or if there are any logs anywhere I can look at to find out why team city thinks it needs to build.</p>