The hung build detection scheme uses both elapsed build time and time-since-log-update to trigger hung-build detection. It appears that for the 1st build on a branch plan, there is no average build time and hence no ability to detect hung builds.

We observed a failure to detect a hung build when the build did not update the log for over two days.  (The average time for this build on other plan branches was ~6 minutes.  The build hang time multiplier was set to 10x and the log timeout was 150 minutes).

I would suggest that for the 1st build on a branch:

A) Ignore the detection based on average build time and use log-update time only, or

B) Use the average build time from a different branch plan (or the average build time of all branch plans)