Someone on our team had a similar problem with a cable ADSL connection. The connection was usually good, but at a certain time of day it became flaky for a while. He would often end up with the dreaded missing generation errors.
It's clear that a flaky network connection can cause generations to slip through the cracks and into the abyss. That should never happen. The client should never delete the generation until after it learns that the result has been successfully stored away on the server.
This is a very serious bug, and we need to keep after the DF team until they fix it!