The behavior you are observing is working as designed. In the past, there was an issue related to the file attachment corruption, which was investigated via SPR# TMAICWHDAY and it is fixed in 11.0.1 FP9, 12.0.2 FP4 and 14.0 FP2 release, and because of this fix, the behavior is expected.
You can refer to the following article regarding the file attachment corruption issue.
If it doesn't occur on one server and occurs on another server then I would suggest you to open a ticket with HCL Customer Support for further investigation.