Our builds are currently not correctly catching Hash Sum Mismatches on apt-get update.  We had it setup ot catch that error, abort and try again.  It's an inherent race condition 

It's ticketed here: https://github.com/ros-infrastructure/buildfarm/issues/133 but I expect we'll see several of these errors as we're churning the farm quickly.  

If you get one of these you can expect to get another email within a day saying it's back to normal.  

Sorry for the extra emails we're working to catch this error again. 

Tully