Workaround to receive corrupt file as original format:
1. Change the value of 'enable_alernative_scrub_method' in '/etc/fw/conf/scrub_debug.conf' to '0':
2. Allow Threat Prevention Profile > Threat Extraction Settings > Advanced > Threat Extraction Exceptions > Corrupted files
3. Install the security policy onto the relevant Security Gateway.
This solution has been verified for the specific scenario, described by the combination of Product, Version and Symptoms. It may not work in other scenarios.