Since Artifactory is a Binary Repository Manager, currently our Debian repositories do not support sources. We do not support sources in the sense that once the Debian client retrieved the 'Sources' file, Artifactory treats it as a regular file. This in turn means that this file will not "expire" and therefore whenever the Debian client will look for this file for the checksum purposes, Artifactory will not "go outside" to look for an updated version but rather provide the already cached 'Sources' file. This of course will cause the "Hash Sum Mismatch" and will also be resolved in most cases by deletion of 'Sources/' and not including deb-src as a source through Artifactory.
The easiest way we've found to keep apt from attempting to get the i18n packages is to:
echo 'Acquire::Languages "none";' >/etc/apt/apt.conf.d/99translations
That disables all attempts at locating internationalization files. There are two open Jira tickets open on this issue. Please watch and vote for these issues to see future updates.