Is it possible for the download to /tmp to have a unique name (using something like the detetimestamp)
This would help with attempting to isolate these kinds of errors.
I have seen an issue where 2 jobs run on a single host at the same time and one will download the file, the other will also download the file and while the 2nd instance is streaming to the /tmp the first attempts to unzip and causes the file to appear corrupt as its being downloaded.
Thanks