In the past few days, two of the Amazon EC2 mirrors in my repo set are being stubborn when I try to update them. I get the following messages:

ERROR: unable to update: http://us-east-1.clouds.archive.ubuntu.com/ubuntu/dists/precise-updates/main/binary-i386/Packages.bz2: size check mismatch 1045491 != 1045248
ERROR: unable to update: http://us-east-1.clouds.archive.ubuntu.com/ubuntu/dists/trusty-updates/main/binary-i386/Packages.bz2: size check mismatch 720276 != 712806

If I retry the updates for these two many times, eventually they will complete successfully. I'm not seeing any problems with the remote repos themselves when I try and update an Ubuntu instance directly from them, so I don't think the problem is with Amazon. However, I'm mirroring twenty-two other remote repos and Aptly has no trouble with any of them.