random corrupt archived artifacts

[Douglas Moore]

jenkins version 1.642 on centos 7.1

As a post build step we archive about 30 zips, gzs and isos to a  mounted nfs filesytem on the jenkin server. We are starting to find some of the archived files are corrupted. Its a random occurence.  This is verified because we do a checksum on the files before they are archived. The checksum does not match after archiving. If it matters we are using sha256sum.

Is it possible jenkins has a bug ?  

Any suggestions on how to troubleshoot this ?

thanks

doug